Data from the

NATIONAL HEALTH SURVEY

U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE

Public Health Setvice

series 11

Number 201

Monocular Visual Acuity

Of Persons 4-74 Years

United States -1971-1972

Visual acuity levels with usual correction, if any, as determined in

the opthahnology examination before diIation by race, geographic

region, family income, and other selected demographic variabIes.

DHEW Publication No. (HRA) 77-1646

Health ResourcesAdministration

National Center for Health Statistics

Rockvilie, Md. March 1977
NATIONAL CENTER FOR HEALTH STATISTICS

DOROTHY P. RICE, Director

ROBERT A. ISRAEL, Deputy Director

JACOB J. FELDW, Ph.D., Associate Director for Analysis

GAIL F. FISHER, Associate Director jor the Cooperative Health Statistics System

ELIJAH L. WHITE, Associate Director for Data Systems

ANDERS S. LUNDE, Ph.D., Associate Director for International Statistics

ROBERT C. HUBER, Associate Director for Management

MONROE G. SIRKEN, Ph.D., Associate Director for Mathematical S tatistics

PETER L. HURLEY, Associate Director for Operations

JAMES M. ROBEY, Ph.D., Associate Director for Program Development

ALICE HAYWOOID, Information Officer

DIVISION OF HEALTH EXAMINATION STATISTICS

ARTHUR J. McDOWELL, Director

JEAN-PIERRE HABICHT, M.D., Ph.D., SpeciajAssistant to Director

PETER V. V. HAMILL, M.D., Medical Adviser

JEAN ROBERTS, Chiej Medical Statistics Branch

ROBERT S. MURPHY, Chiej Survey P&znning and Development Branch

ARNOLD ENGEL, M.D., Medical Adviser, Adult Program

COOPERATION OF THE BUREAU OF THE CENSUS

In accordance with specificaticms established by the National Health

Survey, the Bureau of the Census, under a contractual agreement, participated in the design and selection of the sample, and carried out the first stage

of the field interviewing and certain parts of the statistical processing.

Vital and Health Statistics-Series 11-No. 201

DHEW Publication No. (HRA) 77-1646

Library of Congress Catalog Card Number 76-608246
. .

Library of Congress Cataloging in Publication Data

Roberts, Jean

Monocular visual acuity of persons 4-74 years, United States, 1971-1972.

(Vital and health statistics: series 11, Data from the National Health Survey, Data

from the health examination survey; no. 201) (DHEW publication; no. (HRA) 77-1 646)

Caption title.

Bibliography: p.

Supt. of Dots. no.: HE 20.6209:11/201

1. Visual acuity–United States–Statistics. 2. Visually handicapped–United States–

Statistics. 3. Health surveys-United States. I. Ludford, Jacqueline, joint author. II.

Title. III. Series: United States. National Center for Health Statistics. Vital and health

statistics: Series 11, Data from the National Health Survey, Data from the health examination survey; no. 201. IV. Series: United States. Dept. of Health, Education, and Welfare.

DHEW publication; no. (HRA) 77-1646. [DNLM: 1. Vision tests. 2. Visual acuity.

W2 AN148vk no. 201]

RA407.3.A347 no. 201 [RE925] 312’.0973s [312’.6]

ISBN 0-8406 -0083-6 76-608246

For sale by the Superintendent of Documents, U.S. Government Printing Office

Washington, D.C. ‘2o4w - Price $1.30

Stlxk.No. 017-O’2HM30- 1
CONTENTS

Page

Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...1

Ophthalmology Examination.. . . . . . . . . . . . . . . . . . . . . . . . ...3

Visual Acuity Testing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Optotypes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Quality Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

,Findings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

AgeandSex . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ..$

Race . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Ancestry . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Geographic Region . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...11

SizeofPlaceofResidence. . . . . . . . . . . . . . . . . . . . . . . . . . ...14

Income . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...14

Education . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

ComparisonWithPreviousStudies . . . . . . . . . . . . . . . . . . . . . . . . . 18

Other Prevalence Estimates of Defective Acuity . . . . . . . . . . . . . . . . . . 22

Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

ListofDetailedTables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25

AppendixI.StatisticaINotes.. . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

TheSurveyDesign . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...61

Nonresponse . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62

Missing Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ...64

SmaIINumbers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65

SamplingandMeasurementError . . . . . . . . . . . . . . . . . . . . . . ...65

AppendixII. DemographicandSocioeconomicTerms . . . . . . . . . . . . . . . . 66
SYMBOLS

Data not a\'aiIable--------------------------------------- ---

Category not applicablle------------------------------ . . .

Quantity zero --------------------------------------------- -

Quantity more than Obut less than 0.05---- 0.0

Figure does not meet standards of

reliability or precision ---------------------------- *
MONOCULAR VISUAL ACUITY

OF PERSONS 4-74 YEARS

Jean Roberts and Jacqueline Ludford, &z3iorz of Health Examination Statistics

INTRODUCTION

This report on monocular distance acuity

levels of persons 4-74 years of age in the United

States is the first in a series containing national

estimates based on findings from the ophthalmological examination of a national probabilityy

sample of the U.S. population during the first

Health and Nutrition Examination Survey in

1971-1972. The findings for the monocular

acuity levels with usual correction, if any, are

analyzed with respect to age, sex, race, ancestry,

geographic region, population size of place of

residence, annual family income, and education.

The Health Examination Survey, in which

these data were obtained, is one of the major

programs of the National Center for Health

Statistics authorized under the National Health

Survey Act of 1956 by the 84th Congress as a

continuing Public Health Service activity to

determine the health status of the population.

The data systems programs used to cmry out

the intent of the National Health Surveyl

include, in addition to the Health Examination

Survey, the Health Interview Survey, which

collects health information from samples of

people by household interviews and focuses

primarily on the impact of illness and disability

within various population groups; the Health

Manpower and Facilities surveys, which obtain

data on hospitals, nursing homes, and other

resident institutions; and Health Resources Utilization surveys, which obtain information on

persons using and the extent of the use of health

facilities and health manpower.

The Health Examination Survey is one of

these programs designed to collect the kind of

needed health statistics information obtainable

only through direct examinations of probability

samples of the population. From direct examinations, tests, and measurements, data are obtained in this program on the prevalence of

medically defined illness-known as well as

previously unknown or undiagnosed conditions–and on the distributions of a variety of

health-related physical, physiological, and

psychological measurements from which normative data and appropriate cutoff points for what

is abnormal can be determined. Also collected

are medical history, demographic, and socioeconomic data on the sample population under

study with which the examination findings may

be interrelated.

Since 1960 the Health Examination Survey

has been conducted as a series of separate,

consecutive programs called “cycles,” each of

which is Iimited to some specific segment of the

U.S. population and to specific aspects of

health. During the first cycle in 1960-1962, the

prevalence of certain chronic diseases and the

distributions of various physical and physiological measures, including visual acuity, were determined among a defined adult population.z Z3For

that program a national probability sample of

7,710 persons 18-79 years of age, of whom

6,672 (86.5 percent) were examined, was selected to represent the 111 million in that age

segment of the civilian Boninstitutionalized U.S.

population at that time.

The target populations for the second and

third cycles in 1963-1965 and 1966-1970 were,

respectively, the Nation’s noninstitutionalized

children 6-11 years of age and youths 12-17

years of age.4YS In both these programs, the

1
examination was focused primarily on health

factors related to growth and development. For

the second program a probability sample of

7,417 was selected to represent the nearly 24

million noninstitutionalized children in the U.S.

population, o f whom 7,119 (96 percent) were

examined. For the third program a probability

sample of 7,514 was selected to represent the

22.7 million noninstitutionalized youths in the

U.S. population at midsurvey. Of these, 6,768

(90 percent) were examined.

The Health and Nutrition Examination Survey (HANES) program, from which the findings

in this report were derived, was designed to

measure the nutritional status of the U.S.

population of ages 1-74 years and to obtain some

limited information on the general health status

of the entire age group as well as more detailed

information on the health status and medical

care needs of persons age 25-74 years in the

civilian noninstitutionalized population. A description of the specific content and plan of

operation, including sample design, has been

published.6

As in the previous Health Examination Survey

programs, the U.S. Bureau of the Census cooperated in the sample design and in the initial visits

for interviewing at the eligible households in the

primary sampling units (PSU’S) selected in the

various parts of the country. Members of the

field teams of the mobile examination center did

further household interviewing and explaining of

the examination portion of the program. The

selected sample persons for whom appointments

could be made were brought into the specially

constructed mobile examination centers that

were moved into a central location in each of

the primary sampling units. The team that

traveled to the various survey locations throughout the country included professional and paraprofessional medical and dental examiners along

with technicians, interviewers, and management

staff.

The probability sample design used in the

study provided for oversampling, at predetermined rates, among the poor, preschool children, women of childbearing ages, and the

elderly, so that the nutritional status of these

high-risk groups could be more accurately estimated. It further provided for a nationally

representative subset , of 35 of the initially

planned primary sampling units throughout the

United States so that some preliminary national

findings on the nutritional status of the population could be published before the total survey

was completed and so that national estimates

could be obtained from those parts o,f the

examination that were included only in this

35-stand subsample.

During the planning for the HANES program,

Dr. Carl Kupfer, Director, National Eye Institute

(NEI), indicated the interest of that Institute in

obtaining more definitive information than was

currently available on the prevalence and ,clistribution of specific eye diseases and related

conditions throughout the United States as an

aid in setting goals and priorities for future

emphasis in their programs. Consistent with the

overall objectives of the survey, an evaluation of

treatment needs was also incorporated into the

examination.

Two ophthalmologists from NEI, Drs. James

P. Ganley and Arthur F. Garcia, developed the

examination form and standardized protocol for

the ophthalmic examination and were responsible for recruiting and training the examining

ophthalmologists as well as for verifying the

resultant diagnoses and for other aspects of

quality control in this area.

The National Eye Institute decided to discontinue the ophthalmology examination after 35

stands because of problems encountered in

recruiting ophthalmologists to conduct the

examinations and the insufficient number of

staff within the Institute to carry out the

program adequately. While the size of the

sample was not as large as originally planned,

these unique national eye examination findings

do provide the basis for analysis needed to meet

most of the original purposes of this part of the

examination.

For the 35 locations at which the ophthalmological examination was given during the period

between April 1971 and October 1972, a national probability sample of 14,147 persons was

selected to represent the 192.7 million in the

target population age 1-74 years. Despite intensive efforts, only 10,126 of the sample persons

came in for examination. This represents 72.8

percent of the sample persons selected when

2
adjustments are made for the differential sampling rates for the age-, sex-, and income-defined

population subgroups. (The unadjusted overall

response rate was 71.6 percent.)

Surveys conducted by the National Center for

Heidth Statistics, including all previous programs

of the Health Examination Survey, have

achieved higher levels of response than have

been reached for the 35-stand subsample in this

first HANES. The 72.8-percent response rate

fails to meet fully the requirements of the

original probability design. However, following a

policy of remunerating participants–adopted

after the completion of 20 primary sampling

units-there was a significant increase in participation.7 Because of the lower-than-usual re-”

sponse rate, the national estimates of the more

severely visually handicapped in this report will

probably understate slightly the actual prevalence of this disability in the noninstitutionalized population 25-74 years of age.

National estimates in this report are based on

weighted observations; i.e., the data obtained for

each examined person were inflated to the level

of the total population. The estimates have been

calculated as though the examined persons in

each of the age, sex, and income ckisses are a

random subsample of the sample persons in the

same class (appendix I). Although there is

evidence from the eadier examination surveys

and medical history data from HANES that

these are not unreasonable approximations, it is

clear that some estimates are subject to considerable risk of bias when more than one-quarter of

the sample persons in a particular age-sexincome class were not examined.

Even though all examinees 1-74 years of age

were examined and tested by the survey ophthalmologists, visual acuity determinations were

made only for those age 4-74 years. Hence,

findings in this report are based on the examination of the 9,263 persons age 4-74 years at the

time of examination. No attempt was made to

estimate the acuity levels for the 863 examined

children under 4 years of age.

OPHTHALMOLOGY EXAMINATION

At each of the 35 selected locations throughout the country, arrangements were made for 10

different sample persons to come or be brought

into the specialIy designed mobile center for

each of the morning, afternoon, and evening

examination sessions. These included eight

examinees from the nutrition sample (1-74

years) and two from the detailed sample (25-74

years). The ophthalmology examination, which

was one of the first procedures scheduled in

each session, was similar for persons in the

nutrition sample and for those in the detailed

sample except for the refraction component in

which determination was made of best corrected

acuity. The examination for those over 3 years

of age included the taking of an ocular history

regarding previously known eye disorders or

previous eye surgery; a determination of monocular distance visual acuity with usual correction,

if any, and with a pinhole test to determine

correctability for those with acuity less than

20/20; type of motility defects; prescription of

present glasses; dilation, and within 20-70

minutes following diIation, retinoscopy for detailed examinees with acuity less than 20/40 and

spherical trial lens test for nutrition examinees

with acuity less than 20/40; applanation tonometry on examinees 20 years and older; and

examination of the pupils, lids, globes, conjunctival, sclera, corneas, anterior chambers, irides,

and lenses. The pupils were dilated in most

instances for the spherical refraction and retinoscopy tests and the examination of the vitreous

and retina.

Visual Acuity Tasting

In the visual acuity testing of examinees over

the age of 3 years, the survey ophthalmologists

used a standard A-O Project-O-Chart with the

target image (Variable Focus Image and Optotype slides) from the projector focused on a

mirror from which the image was reflected to

the Project-O-Chart screen (above and behind

the examinees) cIearly visible on a second mirror

at eye level in front of the examinee. The optical

distance of the target and the image visible to

the examinee was carefully adjusted to the

standard 20 feet for distance acuity testing

witbin the limited space available in the examining room.

Target optotypes on slides available for this

testing included, in order of examination proto3
col preference for use, Snellen letters, illiterate

E, Landolt ring, and Picture.

Visual acuity testing was done with all light in

the examining room turned off, except for the

overhead lamp on the Reliance Instrument

Stand, which was turned on dim and aimed

toward a wall above and behind the examinee.

Only monocular distance acuity was tested;

the eye not under test was occluded. Corrected

acuity only was determined for the 37 percent

of the examinees who had brought their glasses

or contact lenses. For the 63 percent of examinees without glasses, uncorrected monocular

distance acuity was measured. Thus the available

visual acuity data from this part of the examination is limited to “corrected” vision, denoting

functional acuity or the level at which the

examinees were actually seeing with whatever

correction they were using.

The visual acuity testing was started with the

larger Snellen letters (or other optotype) on the

projector chart; then the projected optotypes

were decreased in size until a complete line

could not be read. If an individual appeared to

have good vision, the examiner began at the

20/30 or 20/25 line and then proceeded to the

20/20 line and smaller.

Visual acuity was recorded as the smallest

complete line read correctly (no more than one

optotype missed), plus any letters read on the

next line (e.g., 20/30+3, rather than 20/25- 3).

In cases where the visual acuity was less than

20/400, the examiner recorded the best acuity–

whether the examinee could see finger counting

and at what distance, hand movements, light

perception with projection, light perception

only, or no light perception.

When because of uncorrected astigmatism an

examinee missed one or two letters on several

lines with successively larger letters, credit was

given for the line with the larger letters just

above the line with the smallest letters in which

no more than two letters were missed. Additional credit was shown for those smaller letters

correctly determined on the line immediately

below.

For purposes of this report the visual acuity

level attained was that corresponding to the line

with the smallest

correctly with no

letters or o~her op{otypes read

more than one error in the line

with the one exception noted

with uncorrected astigmatism.

OptcNypes

above for those

For 95 percent of the visual acuity tests the

target slides with Snellen letter optotypes were

used. The proportion of tests administered using

these letters was lowest among young children

and increased with age from 4 percent at age 4

years to 60 percent at age 6, 92 percent at age 7,

and 99 percent at ages 8-74 (table A).

At ages 4 and 5 years, nearly two-thirds were

tested with the illiterate E targets. When the

illiterate E was not used, testing was more Iikely

to have been done with the picture targets at age

4 years (29 percent of all 4-year-olds) and

Snellen letters at age 5 (24 percent of all

5-year-olds) than with the other optotypes. At

age 6, about 60 percent were tested with Snel]en

letters and about 27 percent with the illiterate E

target. Landolt rings were infrequently used, but

somewhat more often at ages 4-6 years (less than

3 percent) than at the older ages (less than 0.5

percent).

Hence, comparability of visual acuity measures obtained on the three types of targets was

of concern primarily for the younger children

under 7 years of age. Various investigateors have

assessed the comparability and factors affecting

the measurement of visual acuity with different

targets.g -13 While the targets used were not

identical with those used in the present study,

their findings give some indication of the possible effect of the use of different targets on the

precision of acuity measurement among the

young children in the present study. In particular, Jonkersl z of Rotterdam in his study of 173

children 3 years of age and over found the

reliability of visual acuity test results to be best

with letter charts and poorest with picture

charts. Results with the illiterate E were somewhat more reliable than test results on the same

children with Landolt rings. However, both

these targets provided more reliable acuity test

results than the picture charts.

Lippmannl 3 in his studies of 3-5-year-old

children enrolled in day care centers administered

found

steady

by the Office of Economic Opportunity

acuity on all test

increase of visual

methods showed a

acuity rating with

4
Table A. Percent of persons reaching specified visual acuity levels and percent distribution of persons tested by age, accmding” to

optotype used:UnitedStates,1971-1972

I Age in years

Total

4

I

5 6 7 8

I

9-11

I

12-74

Visual acuity level and optotype used

Percent of persons reaching or exceeding

visual acuity level with specific optotype

20120orbetter

Alloptotypes . . . . . . . . . . . . . . . . . . . . .

Snellen letters . . . . . . . . . . . . . . . . . . . . . . .

Illiterate E . . . . . . . . . . . . . . . . . . . . . . . . .

Pictures . . . . . . . . . . . . . . . . . . . . . . . . . . .

20/25 or Mter

Alloptotypes . . . . . . . . . . . . . . . . . . . . . .

Snellen letters . . . . . . . . . . . . . . . . . . . . . . .

Illiterate E . . . . . . . . . . . . . . . . . . . . . . . . .

Pictures. . . . . . . . . . . . . . . . . . . . . . . . . . .

20/30 or better

Alloptotypes . . . . . . . . . . . . . . . . . . . . . .

Sneilenletters . . . . . . . . . . . . . . . . . . . . . . .

Illiterat e E . . . . . . . . . . . . . . . . . . . . . . . .

Pictures . . . . . . . . . . . . . . . . . . . . . . . . . . .

20/50 or poorer

Alloptotypes . . . . . . . . . . . . . . . . . . . . . .

Snellenletters . . . . . . . . . . . . . . . . . . . . . . .

Illiterat e E . . . . . . . . . . . . . . . . . . . . . . . .

Pictures. . . . . . . . . . . . . . . . . . . . . . . . . . .

Persons tested

Alloptotypes, . . . . . . . . . . . . . . . . . . . . .

Snellenletters . . . . . . . . . . . . . . . . . . . . . . .

Illiterate E . . . . . . . . . . . . . . . . . . . . . . . . .

Pictures . . . . . . . . . . . . . . . . . . . . . . . . . . .

Landoltrings . . . . . . . . . . . . . . . . . . . . . . . .

72.8 23.2 40.2 50.8 70.4 76.8 79.6 74.5

58.5

25.7

5.1

27.9

43.5

44.6

3.7

51.9

63.2

34.1

14.6

65.0

71.4

61.1

28.7

88.5

76.9

38.9

100.0

91.9

80.1

50.9

86.5

74.9

29.6

87.7

---

. . .

---

85.5

74.8

31.8

5.4

95.3

84.7

47.3

5.4

93.6

85.7

36.5

14.6

95.8

91.0

61.1

28.7

93.4

92.2

38.9

100.0

95.9

87.1

50.9

92.1

882

32.2

45.8

93.3

. . .

. . .

---

93.5

~

---

..-

. . .

3.3

---

. . .

---

98.4

95.0

84.9

2.1

95.8

93.0

91.6

1.8

93.3

89.4

100.0

2.5

94.7

78.2

74.2

2.7

95.8

100.0

100.0

3.7

92.2

84.4

100.0

4.1

93.5

74.1

45.8

3.5

4.1 3.0 3.8 4.3 3.4

17.4

14.5

1.7

3.8

1.6

6.8

Percent distribution

100.0 100.0 100.0 100.0 IWO I 100.0 100.0

8&9

0.4

0.4

0.3

100.0

84.8

3.9

1.1

0.2

4.2

64.0

29.0

2.8

23.8

63.4

11.7

1.1

60.3

27.3

10.6

1.8

92.0 89.0

7.6 0.6

0.4 0.3

0.1

98.2

0.8

0.0

0.0

advancing age of children. Best results were

obtained with a symbol-type chart not used in

the present study and second best with the

illiterate E. Snellen letter charts were not includedin these clinical studies.

In the present national survey the proportion

of children 4-6 years of age reaching the better

*

acuity levels was generally substantially higher

among those tested with SneIlen letter optotypes than among those tested with the illiterate

Eorpicture charts. The proportion with monocukr acuity of 20/25 or betteron the Snellen

targets was more than twice that in the group

tested with the illiterate E and 6-16 times that

5
with the picture optotypes (table A). The

proportion reaching the 20/30 level or better

was similar on all three types of targets. The

Landolt ring optotypes test was used so seldom that its potential influence r-mthe visual

acuity estimates would be negligible even among

the age group 4-6 years, where it was most

frequently used (but for less than 3 percent even

in that young age group). Regardless of age, all

of the persons tested with the Landolt rings

reached the 20/20 acuity level.

Whether the differences in acuity levels obtained for the younger children on the various

targets used reflected real differences in acuity

levels among the individuals tested, differences

in equivalence or difficulty among the targets

used, or differences in the degree of cooperation

or attention of the examinees, or a combination

of these factors cannot be determined from the

data in this study.

Quality Control

Drs. Ganley and Garcia, senior ophthalmologists from the National Eye Institute (NEI),

were responsible for recruiting the 91 survey

ophthalmologists and for training them in the

standard examination procedures used at the

first 35 examination locations of the Health and

Nutrition Examination Survey.

In addition, the senior ophthalmologists from

NEI developed a protocol for replicate testing

which they carried out at 24 of the 35 locations

to ensure the accuracy of the ophthalmology

examination data, to provide an estimate of its

repeatability or reliability, and to aid in maintaining uniformity in examining procedures.

For this, the examinations of all sample

persons in the first two sessions at each of 24 of

the 35 stands were observed and replicated by

the senior ophthalmologists of NEI who then

evaluated the methods and findings of the

examiners and made the necessary recommendations where needed. The NEI observer conducted the first part of these examinations

simultaneously with the examiner and recorded

his findings for each patient on a separate

replicate form. The fundoscopic examination

was done by the observer when the examiner

had completed his examination of the sample

person; evaluation of the fundoscopic findings

was made without the observer knowing the

examiner’s results.

The examiner was observed for technique,

facility with the instruments, and adherence to

the protocol. Written comments were made on

the observer’s records, including specific problems or questions that arose during the examination. Recommendations to the examiner, if

needed, were made at the end of each session.

At the end of each session, after the examiner’s findings had been transferred to the replicate examination form, the examiner’s evaluation of each exarninee was compared with that

of the observer.

In all, 230 ophthalmology examinations (2.5

percent) of the 9,263 given were replicated.

Visual acuity test results from the replicate

examinations showed a high level of agreement

between examiner and observer findings. Clf the

230 examinees, there was exact agreement on

acuity levels for 94 percent of the monocular

tests (right plus left eye), 1 percent differed by

one acuity level, and 5 percent differed by two

levels. Where there was a disagreement, the

examiner was more likely to have obtained a

higher acuity level than the observer (70 percent

of the tests where there was disagreement).

Testing equipment and illumination were

checked periodically throughout the cycle to be

sure they were in good working order and, met

the required standa~ds.

FINDINGS

Age and Sex

Nearly three-fourths (72.8

civilian noninstitutionalized

percent) of the

population 4-74

years of age in the United St&e~ have distance

visual acuity of at least 20/20 in their better eye

“with usual correction” (figure 1, table 1).

These estimates are based on findings from the

Health and Nutrition Examination Survey of

1971-1972 among a national probability sa:mple

of examinees of whom about one-third (37

percent) were tested with their glasses or contact

lenses and the remaining 63 percent without

correction. Only 2.4 percent had better monocular distance acuity exceeding the 20/20 level.

The prevalence of defective better monocular

dktance acuity of 20/50 or less “with usual

correction” in this total agq range is 3.3 percent,

6
7

1

;

u

>

E

u

~1

15 20 25 2040 50 701002@3400tian

or ~

better 400

ACUITY LEVEL (SNELLEN RATIO)

So

60

20

0

or or

better wom

ACUITY LEVEL (SNELLEN RATlO)

Figure 1. Percent of the population age 4-74 years reaching Figu ra 2. Percent of the population age 4-74 wars reaching

specified acuity levels for usual distance vision in the better

eye: United States, 1971-1972.

includlng 0.2 percent with acuity less than

20/200 on this measure. At rnidsurvey point in

1972, an estimated 6.16 million in the U.S.

population age 4-74 years would have had

distance acuity of 20/50 or less in their better

eye with usual correction and for 0.21 miWon of

these their usual better-eye acuity would have

been less than 20/200 (table 2).

Males tend to have somewhat better visual

acuity than females. The proportion of males

testing at least 20/20 (better monocular acuity

“with usual correction”) is 75.2 percent compared with 70.5 percent among females age 4-74

years while the proportion with defective usual

better monocular distance acuity of 20/50 or

less is 2.9 for males and 3.6 for females (figures

t 2, 3, and 4). Less than 0.1 percent of males

compared with 0.2 percent of females have usual

acuity of less than 20/200 in the better eye.

Across this age range the proportion with

usual acuity in the better eye of at least 20/20

increases steadily from 31.2 percent at 4-5 years

to a maximum of 87.6 percent among young

adults 18-24 years, levels off and then decIines

specified acuity levels for usual distance vision in the batter

eye, by sex: United States, 1971-1972.

abruptly after 45 years to 32.0 percent at age

65-74 years. The low proportion with this IeveI

of acuity among the preschool-age children of 4

and 5 years probably reflects at least in part the

difference in the precise equivalence of the

optotype targets used most frequently for testing them as well as in the cooperation and

understanding of the examinees tested. By age

6-11 years nearly three-fourths (72.5 percent)

have usual better monocular acuity of at least

20/20, a proportion that is also probabIy influenced to some extent by optotype differences

and examinee cooperation, particularly at 6

years and to a lesser extent at 7 years of age.

However, even among those tested with Snellen

letters, the proportion reaching at least 20/20

increased with age from about 50 percent at 45

years to 63 percent at 6 years to 71 percent at 7

years to 77 percent at 8 years and 80 percent at

9-11 years (table A). The proportion with this

level of acuity among males generally exceeds

that among females across the age range with

insignificant exceptions at 25-34 and 65-74

years (figure 3).
100

r

I

80 -

60 -

40 -

20 -

0

1

4.5 6.11 32.17 18-24 25-34

AGE IN YEARS

35-44 45.54 55-&s 65-74

Figure 3. Percent of the population with usual distance vision o{ at least 20/20 in the better eye, byage and sex: United States,

1971-1972.

1-Z

w

u

a

:

20

10

0

4.5 6-11 12-17 18-24 25.34 35-44 4554 55-54 65-74

AGE IN YEARS

Figure 4. Percent of the population with usual distance vision of 20/500 rworse in the better eye, byage and sex: United States,

1971-11972.
The prevalence of defective

or less ‘in the better eve with

acuity of 20/50 20/50 or poorer with the left eye “with usual

usual correction correction” comDared with 64.6 ~ercent reachdecreases steadily with-increase in age from 3.5

percent at 6-11 years to 0.7 percent at 35-44

years then increases to 14 percent at age 65-74

years. The trend with age in the prevalence of

this degree of defective acuity is generaHy

similar among males and females but tends to be

slightly more prevalent among females except at

6-11 years and 55-64 years (figure 4).

With usual correction, the dktribution of

acuity levels for the right and left eyes are

generally similar (table 3), with more than

three-fourths (76.7 percent) showing no difference in acuity level between the two eyes on

monocular tests. When there is a difference, it is

more likely to be of only one level (16 percent)

than of more than one (7 percent) and to be

slightly better in the left than in the right eye.

Among those 4-74 years of age, 66.0 percent

tested 20/20 or better and 5.9 percent tested

ing 20/20 or be;ter and 6.4 per;ent no better

than 20/50 with the right eye.

Race

Negro persons age 4-74 years tend to have

poorer acuity with usual correction than white

persons in the United States (figures 5, 6, and

table 4). Less than two-thirds (65.8 percent) of

the Negroes reached at Ieast the 20/20 level on

better monocular acuity tests compared with

73.6 percent of white persons, w-file 5.1 percent

of the Negro group compared with 3.1 percent

of the white group could not read above the

20/50 leveI. The number of persons of other

races in the population and hence in the sample

was too small .to provide estimates of their visual

acuity sufficiently reliabIe for publication.

Across the age range in the study, the

4-5 S-II 12.17 18.24 2534

AGE IN YEARS

35.44 45.% 55-M

Figure 5. Percent of the white and Negro populations with usual distance vision of at least 20/20 in the better eye, by age:

United States, 1971-1972.

9
r

30

20

10

0

4.5 611 12.17 1S-24 25-34 35-44 45-54 55-64 65-74

AGE IN YEARS

Figure 6. Percent of the white and Negro populations with usual distance vision of 20/50 or worse in the better eye, by age:

United States,,

proportion reaching at least 20/20 with usual

correction in their better eye was less and the

proportion testing no better than 20/50 was

greater among Negro than among white persons

except at age 6-11 years (figures 5 and 6). The

greatest racial difference in acuity is evident

among the youngest and oldest age groups—

under 6 years and 65-74 years.

Among the preschool group age 4-5 years,

only 13.2 percent of Negro compared with 33.9

percent of white children tested 20/20 or better

in their better eye with usual correction; while

at age 6-11 years, 55.7 percent of Negro children

compared with 75.4 percent of white “children,

and at 65-74 years 19.1 percent of Negro

compared with 33.2 percent of white adults

reached that level. The racial differences in these

rates in the three age groups are large enough to

be statistically significant (at the l-percent

level). The racial differences in the proportion

with better acuity (20/20 or better) for age

12-64 years are also present but less pronounced.

Defective acuity with usual correction in the

better eye is seven times more prevalent among

Negro than among white preschool children (7. 1

percent compared with 1.0 percent) and the

rates about twice as great among Negro as white

1971-1972.

adults age 65-74 years (27.6 percent compared

with 12.8 percent). In the most severely defective groups unable to read above the 20~400

level which wouId include most of the “legally”

blind, there were 3.5 Negro adults age 65-74

years for every white adult with this degree of

impairment. At age 12-64 years there was: less

difference between the two races in the prevalence of this degree of defective acuity although the rates were consistently higher among

the Negro group.

This pattern of poorer visual acuity with usual

correction among Negro than among white

persons is evident for both males and females

and is most pronounced among the youngest

(4-5 years) and oldest (65-74 years).

At age 65-74 years both white and Negro

women show a slightly higher proportion with

20/20 or better usual vision than white and

Negro men. The proportion with defective acuity of 20/50 or worse was greater among Negro

men than among Negro women, while a slightly

greater proportion of white women than white

men had that degree of visual defect. The

prevalence of severely defective acuity of less

&a.n 20/200 was slightly higher

women than among men of both

65-74 years).

among older”

races (at age

10
Ancestry

In the household questionnaire, information

was obtained on the principal ancestry or

national origin for each of those examinees

whose race was not classified as “Negro” by the

census interviewer. From this, estimates of the

visual acuity levels for three of the larger

minority groups including Spanish and Mexican

American, Chinese and Japanese, and American

Indians living off reservations have been obtained. Recent immigrants from Puerto Rico are

included with those of Spanish ancestry. The

sample size is not large enough to provide

national estimates in greater ethnic detail and

even for these three groups, the survey sample is

not large enough to provide estimates sufficiently reliable to assess ethnic differences in

visual acuity. The population size, relation between the ancestry and racial classifications, and

the acuity levels of these ethnic or ancestry

subgroups are shown for adults 18-74 years of

age in table 5. The findings are generally similar

among children.

Of the three ethnic subgroups, the Orientals–

Chinese and Japanese–have the lowest proportion with better as well as with poorer acuity

(better eye with usuaI correction), while the

American Indians have the highest proportion in

both acuity groups. However, because of the

small number of persons reporting themselves to

have such ancestry in relation to the size of the

sample, the precision of the national estimates

of acuity levels for many of them is below the

level usually published in this series and relatively large differences in prevalence rates probably reflect sampling variability alone and not

actual ancestry or ethnic differences in visual

acuity.

Geographic Region

Children and youths under 18 years of age in

the South generally have somewhat better usual

visual acuity in the better eye than do those in

the other three regions of the country. The

proportion with acuity of at Ieast 20/20 is

greater at age 4-17 years and the proportion

with defective acuity of 20/5 O or poorer is lower

at age 6-17 years in the South than elsewhere

(figures 7, 8, and table 6). This regional pattern

in the distribution of acuity is present but less

marked among boys than that shown for both

sexes combined, but is not consistent among

girls.

Among adults 18-74 years of age the regional

differences in the distribution of visual acuity

are less consistent than those for children and

youths. However, the proportion of adults with

defective acuity of 20/50 or poorer is consistently lower among those in the Midwest than

elsewhere across the 18-74-year age range for all

adults and across the 45-74-year range for men

and women.

In three of the four regions the proportion of

persons with visual acuity 20/20 or better

reaches a maximum of 84-88 percent among

younger adults 18-44 years, while in the South

the maximum is reached earlier among youths

12-17 years where the rate slightly exceeds that

in the 18-44-year age range. From the maximum

rate the proportion with acuities of 20/20 or

better decreases consistently with age until by

65-74 years the proportion with that degree of

usuaI acuity in the better eye is reduced to

28-36 percent in the four regions.

The proportion with defective acuity of

20/50 or poorer is at a minimum of 1-2 percent

among younger adults 18-44 years, then generally consistently increases with age and is at a

maximum among the oldest age group, to 65-74

years, with rates ranging from 8-20 percent in

the four regions. This age-related trend in both

better and defective visual acuity is generally

consistent among males and females in each of

the regions.

The regional distribution of visual acuity

among white persons in this country is generally

similar to that deseribed above for persons of all

races combined, but is somewhat less consistent

among the Negro population.

Among white preschool-age children, the proportion with usual acuity of at Ieast20/20 in the

better eye is greatest in the South–51.3 per

100–compared with rates ranging from 15.9 in

the West to 38.4 in the Midwest. The wide

variability in these rates is probably partly due

to differences in targets selected for use in

testing. At the other end of the visual acuity

scaIe, no white preschool children in the South

had usual defective acuity of 20/50 or poorer

while the proportion in the other three regions

ranged from 1 percent or less in the West and

11
100

80

5

60

8

c

IJJ

40

20

0

100

80

+

60

5

v

:

L

40

20

0

Northeast Midwest South

12.17 years

100

80

60

40

20

0

100

80

60

40

20

0 I

west

100

80

60

40

Northeast Mldwesl South West

GEOGRAPHIC REGION

6-11 years

Midwest South

18.54 years

West

Northeast M,dwesr South west

65.74 years

Northeast Midwest South West

GEOGRAPHIC REGION

Figure 7. Percent of the white and, Negro populations age 4-74 yealrs with at least 20/20 usual distance vision in the better eye, by age

and geographic region: United States, 1971-1972,

12
40— 4-5 years 40- 6-11 years

~ White

30 ~ ~egro 30

2

u

g 20 20

E

10 - 10

0

Northeast Midwest South west Northeast Midwest south West

40 12.17 years 40 1S-54 years

30 - 30

1- Z

: 20 20

LLJ

10 10

0

Northeast Midwest South West Northeast Midwest .%uth West

40

[

55-64 years 40

30

t

30

10 -

: .,

0

Northeast Midwest South West

GEOGRAPHICREGION

20

10

0

Northeast Midwest South west

GEOGRAPHIC REGION

Figure 8. Percent of the white and Negro pqmlations age 4-74 years with 20/50 or worse usual distance vision in the better eye, by

age and geographic region: United States, 1971-1972.

Midwest (0.8 and 1.0 per 100, respectively) to

2.3 per 100 in the Northeast.

The regional pattern in the distribution of

visual acuity among Negro children and youths

differs somewhat from that for their white

counterparts and is less consistent. Among the

Negro preschool-age children the prevalence of

20/20 or better acuity is about the same–13.5

to 15.5 per 100–in all regions except the

Northeast where the rate is lower (3.8 per 100).

The highest prevalence of 20/20 or better vision

among Negro children 6-11 yeas of age is in the

West (75.0) and South (64.4) with the lower

rates in the Northeast (48.7) and in the Midwest

(32.8); in contrast, the highest rates for acuity

of 20/20 or better among Negro youths 12-17

13
years of age are in the Midwest (80.3) and South

(81.8) and the lowest rates are in the West

(68.7).

Between the ages of 18 and 54 years there is

little regional difference in the proportion of the

white population with usual acuity of 20/20 or

better, while among Negro younger adults those

in the South show a somewhat higher prevalence

rate for better acuity than do those in the other

regions. The proportion with defective acuity of

20/50 or less in the better eye with usual

correction is highest in the West, particularly for

Negro adults.

At 55-64 years of age both white and Negro

adults in the Midwest, tend to have somewhat

better usual acuity–relatively more 20/20 or

better, and fewer with defective acuity of 20/50

or poorer—than do those in the other three

regions,

Among the oldest age group, 65-74 years, the

proportion with defective acuity (usual better

monocular vision of 20/50 or less) is substantially greater among Negro adults in the South

(38.9 percent) and Northeast (25.0 percent)

than in the West (16.1 percent) or Midwest (9.7

percent). Regional differences in the distribution

of visual acuity are less marked among older

white adults. However, relatively fewer of both

white and Negro adults in the Midwest than

elsewhere have that degree of defective acuity.

The prevalence of usual monocular visual

acuity levels of 20/20 or better (in the better

eye) is greater among white than among Negro

children and among youths 4-17 years of age in

each of the four regions except in the West for

children 6-11 years of age (figure 7). Negligible

white-Negro differences in these better acuity

rates may be seen among preschool children, 4-5

years, in the West and 12-17-year-old youths in

the Midwest.

Among adults the regional pattern of the

white-Negro differences in the proportion with

usual visual acuity of at least 20/20 in the better

eye is less consistent than that shown for

children and youths. Between the ages of 18 and

54 years, there is little difference in the prevalence of usual acuity of 20/20 or better between

white and Negro adults, in each of the regions,

except in the West at 45-54 years, where the

proportion of Negro adults with this level of

better acuity is significantly less than that in the

other regions. By 65-74 years of age, except in

the Midwest where the prevalence rates for the

two races are similar, the proportion of white

adults with 20/20 or better usual acuity consistently exceeds that for Negroes in each of the

regions. Prevalence rates for defective acuity

(20/50 or poorer) in the South and Northeast

are more than twice as great for Negro as for

white persons 65-74 years of age, while the

proportion with this degree of defect among

Negroes in the Midwest and West is only

negligibly greater than for their white counterparts.

Size of Place of Residence

There is no consistent pattern of differences

in the distribution of usual visual acuity (better

eye) by size of place of residence for the ‘U.S.

civilian noninstitutionalized population age 4-74

years. Among persons living in urbanized areas,

72.4 percent have usual monocular acuity of

20/20 or better, compared with 73.2 percent in

urban communities outside of urbanized areas

and 73.1 percent in rural areas. The proportions

with defective acuity of 20/50 or poorer are

similarly close: 3.5 percent for those in urbanized areas, 3.6 percent in nonurbanized areas,

and 3.0 percent in rural areas. The differences in

rates are not statistically significant nor is there

a consistent pattern in visual acuity rates by age,

race, or sex (table 7).

Income

There is a consistent relationship between the

level of family income and usual visual acuity of

persons 4-74 years of age in the United States.

The proportion with usuaI acuity of at least

20/20 in the better eye increases with the size of

the annual family income from 60.1 percent

among those in families with income under

$5,000 to 70.5 percent in the middle incc)me

brackets to 79.5 percent among those with

income of $10,000 or more per year, while the

proportion with defective acuity of 20/50 or

poorer decreases from 7.6 percent in the lowest

income bracket to 3.3 percent for those with

incomes of $5,000 to $10,000 to 1.7 percent

among those in the highest income brackets

(table 8 and figure 9).

14
30 ~

80

70

60

+ 50

z

8

a

~ 40

30 -

20

10 –

o—

4.5 years 6.11 years 12.17 years 1S.44 wars

AGE GROUP

4554 years 55.64 years

r~ Lessthan$5WI

[

~ $5,rJlJ@$9,9gg

~ SIO,LMOOrinOre

65.74 years

Figure 9. Percent of the population age 4-74 years with at least 20/20 usual distance vision in the better eye, by age and family

income: United States, 1971-1972.

The relationship of usual acuity and income is

generally similar among both males and females.

Among males the increase in the proportion

usually testing 20/20 or better from the lowest

to the highest income group is from 64.4

percent to 81.1 percent while the proportion

with defective acuity of 20/50 or poorer decreases from 8.9 to 1.3 percent. Similarly among

females, the proportion with usual acuity of at

least 20/20 increases from 57.0 to 77.8 percent,

while those with defective vision decreases from

6.7 to 2.0 percent from the lowest to the highest

income group.

This pattern of association of usuql acuity

with income is generally consistent over the age

range in the study but tends to be somewhat

stronger among preschool-age children 4-5 years

and adults in the middle age group 45-64 years.

Except for women in the older age group, 55-74

years, and males age 12-44 yeqs, the proportion

with usual acuity at least 20/2 O in their better

eye is highest in the highest income groups. The

proportion with defective acuity testing no

better than 20/50 with their usual correction, if

any, is significantly higher among persons with a

family income of less than $5,000 per year.

Among the white population the association

of usual acuity and income, except among the

preschool-age group, is more consistent than for

the total population. However, exceptions to

this pattern are evident among men age 18-44

years, girls age 4-11 years, and women age 55-74

years (figure 10 and table 8).

Among the Negro population only for those

55-64 years of age is this pattern of increase in

better acuity with increased income consistent.

Education

There is a positive association between usual

visual acuity and education level attained by the

head of the household similar to that shown

with family income (tables 9, 10, and figure 11).

The proportion of persons 4-74 years of age

15
30 –

4-5 years

~ White

~ Negro

20

l’-

Z

v

k

4.

10

,,,.,,,.,,

,,,.,,,,,.

,.,.,,,,

:,:.:,:,:,

,.,,,,,,,.

:,:,,,::,

,,,,,,,.

::::,:::::

,.,,,,,.,.

,.,,,.,,,,

,,,,,.,,,,

0 —

30

20

10

0

1844 years

o

30

20

iZ

w

v

K

u

L

ANNUAL FAMILY INCOME IN THOUSANDS

30

20

&11 years 12-17 years

20

10

I

45.54 vears

30

20

10

0

658.74 years

1

—

—

UJg &

v$~

ANNUAL FAMILY INCOME IN THOUSANDS

Figure 10. Percent of the white and Negro populations age 4-74 years with 20/500 rworseusual distance vision inthebettereye, by

egeand family income: Urlited States, 1971-1972.

16
100r

4-5 years

100r

20

0

None Elementary High Collegs

school

100

r

None Elementary High College

school

100 r

65-74 years

80

t

None Elementary High College

EDUCATION OF HEAD OF HOUSEHOLD

6-11 wars

100

r

12-17 years

None Elementary High College

schwl

45-54 years

None Elementary High College

school

60

t5564 years

None Elementary High College None Elementary High College

school school

EDUCATION OF HEAD OF HOUSEHOLO EDUCATION OF HEAD OF HOUSEHOLD

Figure 11. Percent of the population age 4-74 years with at least 20/20 usual distance vision inthebetter eye, byageandaducation

ofhead of household: United States, 1971-1972.

with usual acuity of at least 20/20 in the better extremes of the education groups decIined from

eye increases from 36.5 percent among those 20.9 to 1.7 percent.

whose household head had no formal schooling This pattern of association of usual visual

to 79.9 percent among those with some college acuity with this socioeconomic indicator (educaeducation, while the proportion with defective tion of househoId head) is generally similar for

acuity no better than 20/50 in these two males and females and across the age groups in

17
this study. It is also more consistent

white than the Negro population.

among the

Among the adults 18-74 years of age, the

association between visual acuity and the education of the examinee shown in table 10 is similar

to that with educational level of the head of the

household. These data are included for comparability with acuity data published for adults from

the 1960-1962 Health Examination Survey.

Comparison With Previous Studies

Monocular visual acuity was measured with

and without correction (the individual’s own

glasses or contact lenses) in the 1!360-1 962

Health Examination Survey among the national

probability sample representative of the civilian

noninstitutionalized population of adults age

18-79 years and in the 1966-1970 Health Examination Survey among the national probability sample representative of the noninstitutionalized population of youths age 12-17 years.

National estimates of the distribution of

visual acuity levels in the better eye with usual

correction, if any, from these two earlier studies

are shown in tables 11 and 12 along with

comparable data from the present study.

The apparent improvement shown in usual

visual acuity of U.S. youths and adults in the

present study over findings for these age groups

in the population in the earlier national surveys

may be the resultant of a number of factors that

need to be considered in interpreting these data.

These changes probably reflect improvement in

eye care and in socioeconomic conditions among

the population as well as differences in testing

methods and examiners among the surveys.

Moreover, the sampling variability for some in

those age groups in the present survey is

somewhat larger than in the previous surveys

because of the smaller sample size in those

groups. There is evidence from the quality

control of the present study that the ophthalmologist examiners tended to obtain slightly

higher acuity levels than did the more experienced observers. On this basis it might be

assumed that the data in all three surveys will

somewhat overestimate the proportion reaching

the better acuity levels and that the overstatement may be somewhat less in the present than

in earlier studies because of the greater skill of

the examiners in the present study.

Among youths 12-17 years of age, some

improvement in usual visual acuity level may be

seen in the present survey from that founld in

the preceding national study, the midpoint for

which was approximately 4 years earlier. The

proportion of boys with usual acuity of at least

20/20 in the better eye increased 5 percent

(from 82.3 percent to 86.6 percent), while the

proportion with usual acuity no better than

20/50 decreased 38 percent (from 3.7 percent to

2.3 percent, figure 12). Girls of that age showed

a negligible improvement of less than 1 percent

in the proportion with usual acuity at least

20/20 from 78.3 percent to 79.0 percent, while

the prevalence of defective acuity no better than

20/50 with usual correction decreased about 40

percent from 5.3 percent to 3. ~ percent (figure

13).

From the survey among adults completed 10

years earlier, consistent improvement in usual

acuity level that generally increased ~th age

may be seen in the present study findings for

men from age 35 years and women 25 years and

over.

Among men 35 years and. over the proportion

testing at least 20/20 with usual acuity in the

better eye shows increases ranging from :2.8

percent at 35-44 years to 16.9 percent at 55-64

years, while the proportion with usual acuity no

better than 20/50 shows decreases ranging from

16 percent at 45-54 years to 61 percent at 35-44

years.

The proportion of women with usual acuity

of at least 20/20 within each age group increased

consistently between 1960-1962 and

197 1-1972; gains ranged from 3 percent at age

25-34 years to 48 percent at 65-74 years. The

proportion with defective acuity no better than

20/50 decreased from 1960-1962 to 1971-1972

at each age from 25 years on; the percentage

reductions ranged from a low of 23 percent at

65-74, years to a maximum of 59 percent at

55-64 years.

Since only uncorrected acuity levels were

measured in the 1963-1965 Health Examination

Survey among the national probability y sample

representative of the noninstitutionalized (children 6-11 years of age in this country, monocular acuity levels obtained in that earlier survey

shown in table 13 are not comparable with those

18
100

90

80

70

1-

Z

w

v

u

Ill

a. 60

50

40

30

0

20

1-

i?l

v

a

10

~

0

Males, better monocular,

at least 20/20

— 1971.1972

1966.1970 and . . . . . . .

1960.1962

I I I I I I I I

5 15 25 35 45 55 65 75

AGE IN YEARS

Males, better monocular,

20/50 or worse ..

— 1971-1972 . .

.. .

. . . . . . . 1966.1970 and ..

1960-1962

,.

. . .

. . .

. .

. .

. ...”

. ..”

. ..”

●

. . . . . . . . . . . . . . . . . . . .

6 15 25 35 46 55 65 75

AGE IN YEARS

Figure 12. Percent of males age 12-74 years with usual distance acuity of at least 20/20 and percent with 20/50 or worse in the better

eye, by age from the present and previous national surveys: United states, 1971-1972 (12-74 years), 1966-1970 (12-17 years), and

1960-1962 (18-74 years).

19
90

80

70

60

2

:

50

E

L

40

30

20

.

.

0

20

b

E

u 10

a

:

—.

Females, better monocular,

at least 20/20

— 1971.1972

.,, . . . . 1966.1970 and

1960.1962 “.

‘.

‘.

‘,

[ I I I I I I

5

J

15 25 35 45 55 65 75

AGE IN YEARS

..

..

Females, better monocular, . . .

20/50 CMworse ,.. ”

...

_ 1971.1972 . . .

. . . . . 1966.1970 and . . .

. . . .

. . . .

. . . . . .

.

. .

. ..”

,..

. . . . . . . . . . . . . . . . . .

n I

5 15 25 35 45 55 65 75

AGE IN YEARS

Figure 13. Percent of females age 12-74 years with usual distance acuity of at least 20/20 and percent with 20/50 or worse in the

better eye, by age from the present andprevious national surveys: United States, 1971 -1972 (12-74 years), 1966-1970 (12-17

years), and 1960-1862 (18-74 years).
100

W

So

70

1- 2

8

a

gao

50

40

30

0

Both sexes, ●t least 20/20

— Estimatd binocular 1971-1972

-—— Binocular 1960-1962,1966.1970

—.- Better monocular 1971.1972

. . . . . . . Better monocular 19S0-19S2, 1%S-1970

-.

..

...

..

..

,.

5 15 25 35 45 55 65 75

AGE IN YEARS

20- Both sexes, 20/EO or worse

E$timatad binocular 1971.1972

..

Binacdw 19S0.19S2, 19SS-1970 ..””/ —-- . . /

—.— Better monocular 1971-1972

;

. . . . . . . Better monc.whr 19S0.19S2, 1966-1970

v 10 -

a

u

-.40

& ....

5 15 2s 35 4s 65 t% 7s

AGE IN YEARS

Figura 14. Estimated percent of population age 12-74 years with usual binocular and parcent with usual better monocular of at least

20/20 or of 20/!YJ or worse, by aga from presant and previous national sway= United Statas, 1971-1972 (1 2-74 yaars), 1966-1970

(12-17 yaars), and 19S0-19S2 (18-74 years).

21
for children in the present study. At least some

if not all of the increase between the two survey

periods may reflect the corrected acuity status

of these children at the time of the earlier

survey, since about 10 percent of the children

were known to have glasses or contact lenses.

Other Prevalence Estimates of Defective Acuity

In the three preceding national surveys, measures of binocular acuity were obtained. This

measure was not included in the ophthalmology

examination given in the present Health and

Nutrition Examination Survey because that part

of the examination was concerned principally

with the detection of ocular pathology not

previously attempted in the earIier surveys.

However, if the relationship between monocular, better monocular, and binocular acuity

from the preceding survey findings also were to

exist in the target population for the present

study, the improvement in usual acuity levels of

the adult population between the national estimates from the present study in 1971-1972 and

those from the 1960-1962 survey is even greater

from age 35 years on than that shown by the

better monocular acuity (figure 14).

The estimate for those with usual binocular

acuity less than 20/200 from the present study

would just slightly exceed the estimate of 0.2

per 100 obtained from the better monocular

acuity findings.

No measure of near visual acuity was obtained

in the present study. Consequently, it is not

possible to determine from these data the

proportion of the population who have both

defective distance and near acuity. From the

1960-1962 Health Examination Survey among

adults age 18-79 years there were 5.0 percent

with usual binocular distance acuity of less than

20/40 and 9.1 percent with usual near acuity of

less than 14/28. This included 2.8 percent who

had at least that degree of visual defect at both

near and distance or a total of 11.3 percent who

had that degree of defect at near or distance.

The trend with age for those with one or both

types of visual defect is similar to that for

defective distance acuity (table 14). It increases

slowly among young adults from 1.8 percent at

18-24 years to 6.5 percent at 35-44 years. The

sharp increase at 45-54 years reflects the increase in defective near acuity. The proportion

then increases steadily from 29.2 percent at

45-54 years to 63.9 percent at 75-79 years.

SUMMARY

This report contains national estimates of the

distribution of monocular distance acuity with

usual correction, if any, among the civilian

noninstitutionalized population age 4-74 years

in the United States, based on findings from the

ophthalmologic examination in the Health and

Nutrition Examination Survey of 1971-1972.

The findings for the usual acuity in the better

eye are analyzed by age, sex, race, ancestry,

geographic region, population, size of place of

residence, annual family income, and education.

For the first 35 examination locations of the

Health and Nutrition Examination Survey of

1971-1972, a national probability sample of

14,147 persons between the ages of 1 ancl 74

years was carefully and scientifically selected to

represent the 192.7 million in the civilian

noninstitutionalized population of that agc in

the United States at the midsurvey time. The

10,126 persons who came in for examination

represent 72.8 percent of the sample persons

selected when adjustments are made for the

differential sampling rates used in the age-, sex-,

and income-defined population subgroups. The

visual acuity measurements were obtained on

the 9,263 examinees over the age of 3 years.

Major findings from this study include:

●

●

●

Nearly three-fourths (72.8 percent) of the

U.S. population 4-74 years of age have

distance visual acuity of at least 20/20 in

their better eye with their usual correction,

if any. For these tests about one-third wore

their own glasses or contact lenses, and

two-thirds were tested without correction.

About 3 percent (3.3 percent) or &16

million persons in the total 4-74-year age

range have usual acuity of 20/50 or less in

their better eye including 0.2 percent or

0.21 million persons whose usual acuity is

less than 20/200 in their better eye.

Across the age range the proportion with

visual acuity in the better eye with usual

correction, if any, of at least 20/20 increases steadily from 31.2 percent at age

22
4-5 years to a maximum of 87.6 percent

among young adults 18-24 years of age,

levels off, and then declines from 45 years

on to 32.0 percent at age 65-74 years.

. Defective acuity of 20/50 or poorer (in the

better eye with usual correction) decreases

steadily with age from 3.5 percent at 6-11

years to 0.7 percent at 35-44 years then

increases to a maximum of 14.1 percent at

age 65-74 years.

. The trend with age is similar for males and

females in the population but proportionately more males than females have acuity

of at least 20/20 and fewer of 20/50 or

less.

. Negro persons age 4-74 years have poorer

visual acuity (better eye) with their usual

correction, if any, than do white persons.

Previous national surveys in which both

uncorrected and corrected acuities were

obtained for each examinee would indicate that this probably reflects differences

in the availability or utilization of eye care

for the two races. The greatest racial

difference in acuity is evident among the

youngest and oldest age groups (under 6

years and 65-74 years).

. Children and youths under 18 years of age

in the South generally have somewhat

better usual acuity (better eye) than do

those in the other three geographic regions

of the country. The geographic pattern in

the distribution of visual acuity among

adults is less consistent than that for

children and youths. The proportion of

adults with acuity 20/50 or poorer in the

better eye with usual correction is consistently Iower among those in the Midwest

than elsewhere across the 18-74-year age

range.

. Population size of place of residence is not

correlated with visual acuity levels. The

distribution of usual visual acuity among

persons in rural areas is similar to that

among persons in urbanized areas and

urban places outside of urbanized areas.

. Both education and famiIy income show an

association with usual visual acuity. Persons

in families with the Iowest income and

whose household head has the least education have the highest proportion with

defective acuity (better eye with usual

correction, if any), whiIe those in families

with some college education and those in

the highest income level families have the

lowest proportion with usual defective

acuity.

. Comparison of the visual acuity findings

among U.S. adults 18-74 years of age in

1971-1972 with those from 1960-1962

shows consistent improvement from 10

years ago in the usual (better monocular)

acuity levels for men from 35-74 years and

for women 25-74 years. Some improvement in acuity is also evident among

youths 12-17 years of age in the present

study from comparable findings among

that age group of the population from the

1966-1970 National Health Examination

Survey. These trends probably reflect improvement in eye care and in socioeconomic conditions as well as differences in

testing methods and examiners in the various surveys.

000

23
1National Center for Health Statistics: Origin, program, and operation of the U.S. National Health Survey.

Vital and Health Statistics. PHS Pub. No. 1000-Series

l-No. 1. Public Health Service. Washington. U.S. GovernmentPrinting Office, Aug. 1963.

2Nation~ Center for He~th Statistics: plm ad

initial program of the Health Examination Survey. Vital

and Health Strztktz”cs. PHS Pub. No. 1000-Series l-No. 4.

Public Health Service. Washington. U.S. Government

Printing Office, July 1965.

3National Center for Health Statistics: Cycle I of the

Health Examination Survey: Sample and response,

United States, 1960-62. Vital and Health Statistics. PHS

Pub. No. 1000-Series 1l-No. 1. Public Health Service.

Washington. U.S. Government Printing Office, Apr.

1964.

4National Center for Health Statistics: Plan, operation, and response results of a program of children’s

examinations. Vital and Health S tatrktics. PHS Pub. No.

1000-Series l-No. 5. Public Health Service. Washington.

U.S. Government Printing Office, Oct. 1967.

5National Center for Health Statistics: Plan and

operation of a Health Examination Survey of U.S.

youths 12-17 years of age. Vital and Health Stattitics.

PHS Pub. No. 1000-Series l-No. 8. Public Health

Service. Washington. U.S. Government Printing Office,

Sept. 1969.

6 Nation~ centerfor He~th Stattitics: p~, and

operation of the Health and Nutrition Examination

Survey, United States, 1971-1973. Vital and Health

Statistics. Series 1-Nos. 10a and 10b. DHEW Pub. No.

(HSM) 73-1310. Washington. U.S. Government Printing

Office, Feb. 1973.

7National Center for Health Statistics: A study of the

effect of remuneration upon ‘response in the Health and

Nutrition Examination Survey, United States. Vital and

Health Statistics. Series 2-No. 67. DHEW Pub. No.

(HRA) 76-1341. Washington. U.S. Government Printing

Office, Oct. 1975.

8Sloan, L. L.: Measurement of visual acuity. Arch.

Ophthalmol. 45:704-725, June 1951.

9Sloan, L. L.; Rowland, W. M.; and Altman, A.:

Comparison of three types of test target for the

measurement of visual acuity. Q. Rev. OphthalmoZ.

8(1):4-16, Mar. 1952.

10 Radideau, G. F.: Differences in visual acuity measurements obtained with different types of targets.

PsychoL itfonogr.69(10): 1-12, 1955.

11Westheimer, G.: Visual acuity. Ann. Rev. P~choL

16:359-380, 1965.

12Jonkers, G. H.: The examination of the visual

acuity of children. Ophthalmologz”ca 136:140-144, Sept.

1958.

13 Lippmann, O.: Vision screening of young children.

Am. ]. Public Health. 61(8): 1586-1601, Aug. 1971.,

24
LIST OF DETAILED TABLES

Table 1.

2.

3.

4.

5.

6.

7.

8.

9.

10.

11.

12.

13.

14.

Percent distribution of the population age 4-74 years reaching specified acuity Iwels for usual distance vision in the

better eye, according to age and sex, with standard errors for totals: United States, 1971-1972 . . . . . . . . . . . .

Number in the population age 4-74 years reaching specified acuity levels for usual distance vision in tha better eye,

byageand sex: United States,1971-1972 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent of the population age4-74 years reaching specified visual acuity Ievelsin the right, Ieft, and better eye, by

ageandsex: United Statas,1971-1972 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent distribution of the population age 4-74 years reaching specifid acuiWiwels forusual dis@ncevision in the

&ttereye, according torace, age, andsex, with fiandard errors: Unitd States,l97l-l972 . . . . . . . . . . . . . .

Percent of the population age 18-74 years reaching at leaw20/20 ornobetier than 20/Wwith usual,tistance visual

acui~in thektter eye, byancest~and race, with standard errors: United States, 1971-1972 . . . . . . . . . . . .

Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better aye, by

geographic region, age, race, andsex, with stindard errors: Unitd StaWs, l97l-l972 . . . . . . . . . . . . . . . . .

Percent of the popu Iation age 4-74 years reaching specified acuity levels for usual distance vision in the bettar eye, by

size ofplace ofresidence, age, race, andsex, with standard errors: United States, 1971-1972 . . . . . . . . . . . . .

Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

family income, age, race, and sex, with standard errors: United States, 1971-1972 . . . . . . . . . . . . . . . . . .

Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

education of head of household, age, race, and sex, with standard errors: Unitad States, 1971-1972 . . . . . . . . .

Percent of population age 18-74 years reaching specified acuity levels for usual distance vision in the better aye, by

education of person, age, and sex, with standard errors: United States, 1971-1972 - . . . . . . . . . . . . . . . .

Percent distribution of adults age 18-74 years reaching specified acuity levels for usual distance vision in tha bettar

eye, according toage and sex: United States, 1960-1862 and 1971-1972 . . . . . . . . . . . . . . . . . . . . . . .

Percent distribution of youths age 12-17 years reaching specified acuity levels for usual distance vision in the bettar

eye, according to age and sex, with standard errors for totals: United States, 1866-1970 and 1971-1972 . . . . . . .

Percent distribution of children age 6-11 years reaching specified acuity Iwels for distance vision in the Wter aye,

“without correction” and “with usual correction,” according to age and sex, with standard errors for totals: United

States, 1963-1965 and 1971-1972.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Percent of adults age 18-79 years with defective binocular distance and/or near visual acuity with usual correction,

byageandsex: Unitad States, 1960-1962 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Page

26

27

28

29

33

34

40

43

*

56

57

E8

58

6U

25
Table 1. Percent distribution of the population aga4-74 years reachingspecified acuity levelsfor usualdistance vision in the better eye, acmrding to age and

Age and sex

Sax,with standard errors for totals: United States, 1971-1972

Acuity level–Snellen ratio —

20/1 o Wome

or 20/1 5 20/20 20/25 20/30 20/40 20/50 20/70 20/100 20/200 20/400 than

better 20/400

—

Both sexes Percent distribution

4-74yeara . . . . . . . . . . . . 0.0

0.1

0.0

0.1

12.7 S.o 3.2 1.5 1.0 0.4 0.2

0.2

0.3

0.7

0.2

0.3

0.4

0.2

0.1

0.0

0.1

0.0

0.1

0.5

0.0

0.1

—.

0.0

0.0

0.0

0.2

0.4

0.0

2.4 70.4

30.4

71.5

79.5

83.4

80.3

82.7

70.1

54.6

31.3

72.4

35.2

73.8

82.1

83.5

79.5

84.7

73.8

55.8

30.9

68.5

25.5

69.2

76.3

83.1

81.1

80.6

66.5

53.6

31 (j

0.8

1.0

3.3

4.2

3.9

2.7

1.1

1.4

0.7

2.8

7.7

12.0

8.9

5.8

10.1

9.9

14.8

23.1

27.7

11.4

55.6

9.1

2.8

3.4

3.0

2.7

7.3

113.4

14.3

7.7

52.0

7.9

‘1.9

4.4

2.4

‘1.5

8.5

9.7

14.9

8.4

3.6

2.9

2.8

0.9

1.1

1.3

3.5

5.6

11.9

2.8

0.6

1.2

0.4

0.5

0.6

0.3

1.2

1.9

3.6

1.2

0.6

0.5

0.5

0.5

0.0

0.1

0.5

0.2

1.7

0.3

4-5 years .

&11 years .

12-17 vears

18-24 years

25-34 years

3544 yaar5

45-54 years

66-64 vears

65-74 years

. . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

0.5

1.6

1.5

0.5

0.9

0.3

1.3

2.0

7.3

1.2

Malea

4-74years . . . . . . . . . . . .

4-5years . . . . . . . . . . . ;..

&ll years..........,<. .

12-17years . . . . . . . . . . . . .

l%24yeara . . . . . . . . . . . . .

25-34yeara . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . .

1.0

1.2

4.5

5.0

4.3

3.2

1.3

1.1

0.6

2.0

0.5

0.9

2.2

3.4

3.5

2.2

1.0

1.7

0.8

7.5

10.7

7.5

4.6

11.6

6.5

10.6

23.0

27.1

13.9

3.2

2.5

1.7

0.8

0.8

1.6

2.7

5.2

13.0

3.6

0.1

1.6

1.0

0.1

0.4

0.1

1.6

2.0

6.3

1.8

0.9

1.7

1.9

0.7

1.2

0.6

1.1

2.0

8.0

0.9

0.2

0.5

0.1

0.5

2.0

0.6

0.1

0.5

0.1

1.8

0.5

0.4

1.0

0.4

0.9

3.1

4.2

0.6

0.3

0.2

1.1

0.1

0.3

0.2

0.1

0.1

0.2

0.1

——

0.0

0.0

0.2

0.6

Females

4-74vears . . . . . . . . . . . .

59.3

10.4

3.6

i!.5

3.6

3.8

6.2

11.1

131.8

4-5years .

&ll Yeara .

12-17 yaars

l&24veers

25-34 vears

3S-44 vears

4S54 Vears

55-64 vears

65-74veara

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

7.9

13.1

10.5

7.1

6.7

11.3

18.6

23.1

28.3

4.0

3.3

3.8

1.0

1.6

1.0

4,1

6.4

11.1

1.6

0.5

0.3

0.6

0.3

0.2

1.4

0.9

3,4

0.3

0.9

0.6

1.0

0.0

0.2

0.5

0.4

1.5

0.0

0.3

0.4

0.4

0.5

0.5

0.2

0.1

0.1

0.5

Standard error

Both sexea,4-74Vears . . . .

Meles.4-74years . . . . . . . . . .

Femelee,4-74years . . . . . . . . .

26
Tabla2. Numbarin thepopulation age474yeam reaching specified acuiWlewls forusual distance vision inthebatter eye, byase and sex:

United States, 1971-1972

Acuity Iwels – Snellen ratio

20/1 o Worse

or 20/1 5 20/20 20125 20130 20/40 20/50 20170 20/100 20/200 20/400 than

twtter 20/400

Age and sex

Both sexes Number in thousands

1,904 811 425

40

71

160

56

47

51

214

105

3

17

8

9

67

32

101

10

2

6

30

54

30

4-74 yaars . . .

4-5yaars . . . . . .

&ll years . . . . .

12-17 years . . . .

16-24 years . . . .

26-34 yaars . . . .

35-44 years . . . .

45-54 years . . . .

55-64 years . . . .

65-74 years . . . .

Males

4-74 years . . .

4-5years . . . . . .

6-n years . . . . .

12-17 years . . . .

16-24 years . . . .

2534 years . . . .

3544 years . . . .

45-54 years . . . .

55-64 years . . . .

65-74 years . . . .

Females

4-74 years . . .

4-5years. . . . . .

&ll years . . . . .

12-17 years . . . .

16-24 years . . . .

25-34 years . . . .

3544 years . . . .

45-54 years . . . .

5564 years . . . .

6574 years . . . .

20

20

128,877

2,226

17*759

19,673

18,001

20,715

19,913

16,431

10,190

3>69

64,085

23,279

564

2,966

2,210

1,264

2,588

2,387

3,482

4,284

3,523

10,129

4,306 14,655 5,866 2,811

34

404

362

105

222

79

312

367!

926

1,088

2

200

125

16

51

10

177

173

344

1,713

32

204

237

80

171

68

134

194

563

58

286

104

111

155

78

279

356

477

1,105

220

63

47

115

52

107

270

231

788

66

65

41

63

40

26

172

87

247

43

135

129

117

5

23

108

37

214

268

56

258

825

899

997

655

266

259

93

2.442

4,066

2,269

682

735

775

648

1,721

1,943

1,816

6,722

263

719

681

193

291

310

811

1,084

1,514

2,485

120

317

216

83

90

188

308

453

710

3,381

143

402

465

110

201

122

503

631

604

280

1,364

932

470

1,407

886

1,191

2,006

1,483

13,150

284

1,601

1,278

784

1,192

1,391

2,291

2,289

2,040

1,941

992

244

463

284

178

862

844

814

7,933

2,125

1,277

439

271

491

470

759

1,089

1,002

32

28

58

9

53

105

523

3

28

73

39

145

561

523

521

382

147

92

32

1,866

1,310

9,287

.10,270

8.797

9,562

9,976

8,330

4,876

1,687

64,782

916

8,472

9,404

9,204

11,152

9,937

8,101

5,314

2,282

10

7

13

20 71

37

31

121

9

16

211

17

113

264

376

476

273

118

168

61

12

106

71

106

5

23

55

37

106

3

40

39

46

47

36

17

8

9

39

2

6

22

41

20

27
Table 3. Percent of the population age 4-74 years reaching specified visual acuity levels in the right, left, and better eye, by age and

sex: United States, 1971-1972

Right eye Left eye Better eye

—

20/20 20/25 20/30 20150 20120 20/25 20130 20/50 20/20 20/50

or or or or or or or or or

better

or

better better worse better better better worse better worse

Age and sex

Both sexes Percent

4-74years . . . . . . . . . . . . .

4-5 Veals . . . . . . . . . . . . . . .

6-n Vears . . . . . . . . . . . . . . .

12-17 years . . . . . . . . . . . . . .

18-44Vears . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . .

Males

64.6 88.7 6.4

2.6

5.7

3.7

3.4

6.7

13.2

22.8

6.5

66.0

28.7

68.7

78.4

78.8

60.6

47.3

23.8

68.1

80.2 89.4

91.0

90.8

92.2

94.3

88.9

83.0

63.2

90.5

78.8

35.8

80.8

88.1

88.4

77.1

68.1

47.1

79.7

40.4

83.0

89.8

87.1

76.5

71.1

44.0

78.1

5.9

3.4

5.1

4.5

3.2

6.4

8.5

22.1

5.1

72.8

31.2

72.5

82.8

85.7

71.2

56.0

32.0

75.2

3.3

.—.—

27.7

66.5

78.2

76.7

60.4

46.0

23.0

66.5

92.9

90.4

92.2

94.6

85.7

79.3

63.2

89.3

36.7

80.5

87.8

90.1

79.2

71.8

48.7

81.7

1.9

3.5

2.7

1.5

3.2

4.7

14.1

2.9

——

1,1

3.9

2.3

1.2

3.1

5.2

‘13.5

3.6

4-74years . , . . . . . . . . . . .

4-5Vears . . . . . . . . . . . . . . .

6-n years . . . . . . . . . . . . . . .

12-17years . . . . . . . . . . . . . .

18-44years . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . .

65-74Vears . . . . . . . . . . . . . .

Females

4-74years . . . . . . . . . . . . .

4-5years . . . . . . . . . . . . . . .

6-n years . . . . . . . . . . . . . . .

12-17years . . . . . . . . . . . . . .

18-44Vears . . . ., . . . . . . . . .

45-54Vears . . . . . . . . . . . . . .

55-64Vears . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . .

32.4

70.0

81.4

75.3

64.0

46.1

23.9

62.9

95.6

91.5

93.1

94.3

84.7

79.2

60.9

88.2

2.3

6.1

3.4

3.2

7.0

15.1

24.1

6.5

34.4

70.6

82.9

79.5

64.8

45.4

23.7

64.1

41.8

82.7

91.1

90.9

80.5

69.9

49.7

78.9

92.6

92.0

94.7

94.5

90.9

82.5

63.5

88.5

2.0

5.2

2.9

2.6

5.3

9.9

21.8

6.4

36.2

75.0

86.6

86.7

75.1

56.9

31.5

70.5

22.7

63.0

74.9

77.1

57.1

46.0

22.3

30.9

78.7

86.3

88.7

77.7

65.5

49.5

90.0

89.5

91.1

93.9

86.7

79.5

65.0

2.8

5.0

4.0

3.7

6.4

11.8

21.9

22.8

66.8

73.8

78.1

56.9

49.0

23.9

31.5

78.4

84.4

89.3

78.1

73.5

48.1

89.5

89,8

89.5

94.2

87.1

83.5

63.1

5.0

5.0

6.3

3.8

7.4

7.2

22.3

26.0

70.1

79.0

84.6

67.5

55.3

32.3

2.8

3.1

3.1

1.8

3,4

4.1

14.5

28
Table4. Percent distribution of the population age 4.74 years reaching specified acuity levels forusual distince vision inthe&ttar eye, according to ram,

age, andsex, with standard errors: United States, 1971-1972

Age and sex

White

20170

20/1 o

or

better

0.0

0.1

I

20/1 5 20/20 T20/25 20/30

Worse

than

20/400

20/40 20/50 20/1 00 20/200 20/400

Percent distribution

3.1 1.4

1.8

1.3

0.2

0.9

0.2

1.4

2.1

6.7

1.2

1.0

0.6

1.1

0.3

0.5

0.6

0.4

1.1

1.6

3.4

1.2

8oth sexes . . . . . . . . . . 7.7 0.4

~

0.4

0.6

0.6

0.3

0.0

0.1

0.2

0.0

1.6

0.2

0.2

0.2

0.2

0.9

0.2

0,2

0.3

0.3

0.0

0.0

0.1

0.2

0.0

2.3 71.3 12.5 0.1

0.0

0.1

0.0

0.6

0.0

4-5 years .

&11 years .

12-17 years

1%24 years

25-34 years

35-44 years

45-54 years

55.64 years

6S74 years

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

0.9

0.9

3.4

4.0

3.8

2.s

1.3

1.4

0.8

2.7

33.0

74.5

80.6

83.9

81.2

83.4

70.3

55.2

32.4

73.1

8.0

10.2

8.1

5.9

9.3

9.5

15.0

23.5

28.6

11.3

53.9

8.6

2.6

3.5

2.9

2.5

7.4

10.1

13.6

7.3

3.2

2.1

2.9

0.7

1.2

1.4

3.1

5.8

11.8

Males . . . . . . . . . . . . . . 2.7

4-5years . . . . . . . . . . . . . .

&llyaara . . . . . . . . . . . . . .

72-17vears . . . . . . . . . . . . .

18-24years . . . . . . . . . . . . .

25-34yaers . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . .

46-54years . . . . . . . . . . . . .

55-64vears . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . .

1.2

0.8

4.8

4.6

4.7

2.9

1.5

1.1

0.6

1.9

36.7

75.1

83.2

83.7

81.0

85.2

75.4

55.8

32.2

69.6

28.8

73.8

78.0

24.2

81.5

81.7

65.7

54.5

32.6

7.8

10.0

6.9

4.5

10.3

8.3

10.4

23.6

28.4

13.7

8.3

10.4

9.3

7.3

8.7

10.8

19.2

23.4

28.8

51.4

7.4

1.8

4.6

1.9

1.4

8.6

9.0

14.0

8.1

56.6

9.9

3.4

2.4

3.6

3.6

6.2

11.2

13.2

2.4

2.5

1.6

0.7

0.7

1.6

1.7

5.4

13.0

3.4

0.4

0.3

0.5

1.9

0.5

0.1

0.5

0.1

0.2

0.0

0.6

0.0

0.1

1.8

0.6

0.2

0.4

0.1

1.7

2.0

5.3

1.7

1.8

0.3

0.4

1.0

0.5

0.6

3.1

3.8

0.8

0.3

0.2

1.3

0.1

0.2

0.2

0.1

0.1

0.0

0.2

0.3

Females . . . . . . . . . . . . .

0.6

1.0

1.9

3.4

3.0

2.1

1.1

1.6

0.9

4.1

1.6

4.2

0.7

1.5

1.0

4.4

6.2

10.9

1.4

0.5

0.4

0.6

0.3

0.2

1.5

0.3

3.2

0.3

0.9

0.6

0.6

0.0

0.2

0.4

0.0

1.4

45years . . . . . . . . . . . . . .

&llyeers . . . . . . . . . . . . . .

12-17vears . . . . . . . . . . . . .

l%24vaars . . . . . . . . . . . . .

25-34yeers . . . . . . . . . . . . .

3S44years . . . . . . . . . . . . .

4564years . . . . . . . . . . . . .

6!M4years . . . . . . . . . . . . .

65-74vears . . . . . . . . . . . . .

1.9

1.8

0.2

1.3

0.4

1.2

2.2

7.5

0.3

0.4

0.3

0.4

0.5

29
Table4. Percent distribution of the populaticm age 4.74 years reaching specified acuity Ievels for usual distance vision inthebetter eye, according to race,

age, and sex, with standard errors: United States, 1971-1972-Con.

=

Age and sex

White

20/25 20/30 20/40 20/50 20/70 20/100 20/200 20/400 I

20/1 o

or 20/1 5

better

Worse

than

20/400

20/20

Standard error

0.32 0.17 0.13

0.48

0.32

0.15

0.28

0.34

0.28

0.46

0.66

0.51

0.22

0.67

0.25

0.48

0.72

0.49

0.49

1.49

0.73

0.12

1.03

0.34

0.12

0.33

0.13

0.21

0.76

0.24

0.66

Bmh sexes . . . . . . . . . . 0.01

0.08

0.51 1.09 0.87 0.07 0.02

0.05

0.06

0.02

0.19

0.02

0.02

————

0.05

0.13

0.16

0.02

——

0.10

0.14

0.03

0.48 0.12

4-5 years .

&11 years .

12-17 years

18-24 years

25-34 years

3%$4 years

45-54 years

55.84 years

65-74 years

. . . . . . . . . . . . 0.53

0.29

1.03

1.25

1.13

0.74

0.62

0.74

0.41

0.71

3.37

1,96

1.93

1.51

1.53

1.96

3.34

3.21

1.81

1.21

5.26

2.91

2.38

2.41

2.14

2.00

3.58

4.30

2.33

1.39

5.39

2.34

3.50

1.73

1.57

2.91

4.03

3.38

2.07

1,94

1.46

1.10

1.23

1,08

1,34

2.03

2,50

1.72

0.B9

2.06

1.87

1.02

1.30

2.11

1.90

2.31

3.94

2.45

0.82

3.10

0.74

0.61

0.99

0.80

0.83

1.82

1.74

1.29

0.63

5.25

1.70

0,70

1.69

0,99

0.85

2.21

2.67

1.38

0.70

.—

5,03

1.70

0.92

0.92

1.12

1.42

1.88

2.27

1.89

1.14

0.53

1.12

0.32

0.41

0.51

0.99

1.45

1.41

0.32

0.27

0.35

0.31

0.25

0.02

0.11

0.14

0.01

0.66

0.11

0.79

0.56

0.13

0.44

0.13

0.47

0.74

1.27

0.20

0.19

0,18

0.51

0.14

0.24

0.16

0.13

. . . . . .

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . .

Males . . . . . . . . . . . . .

4-5years .

611years .

12-17 years

18-24 years

25-34years

3!N4 years

45-54 years

55+4 years

6S74 years

. . . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . . . .

0.81

0.19

1.61

1.57

2.04

0.90

0.91

1.10

0.48

0.35

1.23

0.98

0.55

0.59

0.52

0.93

0.90

1.54

1.62

0.48

0.40

0.24

0.42

1.12

0.18

0.09

0.24

0.02 0.03

1.23

0.44

0.17

0.31

0.10

0.73

1.29

1.24

0.27

0.37

0.24

0.97

0.10

0.15

Females . . . . . . . . . . . . . 0.07

4-5 years .

S11 years .

12-17 years

18-24 years

2&34years

35-44years

45-54yeara

55-84 years

6574years

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

0.59

0.51

0.74

1.25

2.56

2.01

1.93

1.78

0.86

1.73

2.84

3.33

2.63

1.64 0.36

0.70

0.45

0.47

0.05

0.22

0.26

0.03

0.57

0.15

0.85

0.84

0.21

0.70

0.25

0.83

1.08

1.80

0.27

0.31

0.25

0.45

0.23

0.11

0.04

0.29

0.24

0.25

0.66

2.07

0.34

0.61

0.41

1.51

1.90

1.61

0.94

0.83

0.58

0.89

0.39

30
Table4. Percent distribution of thepopu[ation age 4-74 years reaching specified acuity levels for usual dietance vision inthebetter eye, according to rem,

age, and sex, with standard errors: United States, 1971-1 972-Con.

Negro

T

20/40 20/50

20/10

or

better

Age and sex Worse

than

20/400

20/15 20/20 20/25 20/30 20/70 20/100 20/200 20/400

Percent distribution

Both sexes . . . . . . . . . . 0.0 2.6 63.2 14.7 10.0 4.4 2.0 1.4 1.1 0.3

0.1

0.6

0.5

0.6

1.0

0.1

0.1

0.2

0.7

0.3

0.0

0.2

4-5yeare . . . . . . . . . . . . . .

Gll years . . . . . . . . . . . . . .

12-17 years . . . . . . . . . . . . .

13-24 years . . . . . . . . . . . . .

2S34years . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . .

4H4years . . . . . . . . . . . . .

55-84years . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . .

13.2

53.8

74.6

81.3

73.5

73.8

66.9

51.6

18.9

66.2

6.2

22.0

14.6

5.1

15.2

13.9

13.7

20.5

16.2

13.1

67.6

12.5

3.0

1.8

4.3

4.6

6.7

12.1

21.6

9.0

5.9

7.6

2.2

1.8

1.0

1.5

6.5

6.5

13.5

4.1

9.7

2.5

2.6

1.2

1.1

2.3

11.6

2.3

13.5

4.7

3.4

0.7

1.7

2.4

0.7

1.2

0.5

0.8

13.9

1.4

1.7

1.2

0.9

0.4

0.6

2.3

2.5

7.2

1.9

2.0

02

0.2

2.1

2.7

2.5

2.7

1.1

0.1

1.9

2.2

5.1

4.6

4.7

1.7

0.2

3.0

0.1

0.2

0.5

2.5

Males . . . . . . . . . . . . . . 0.1

4-5years .

&ll years .

12-17 years

1S24 years

25-34 years

35-44 years

45-54 years

65+4 years

65-74 years

. . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

19.8

64.6

78.3

84.8

69.2

74.8

60.5

62.8

17.0

60.9

5.8

16.0

11.4

4.4

20.9

11.4

11.9

17.1

14.6

16.0

59.5

11.3

1.4

0.9

5.8

3.2

7.4

11.5

24.5

10.8

0.5

0.6

1.3

0.8

0.6

1.7

14.9

2.4

4.7

0.3

0.6

4.4

3.0

0.0 1.1

0.2

3.2

2.8

7.8

1.4

8.3

0.3

2.3

1.8

1.6

0.3

0.8

3.6

3.2

8.9

1.0

0.3

1.5

0.4

0.8

0.1

1.1

1.3

0.3

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . . . . . .

Females . . . . . . . . . . . . .

45years . . . . . . . . . . . . . .

Gll years . . . . . . . . . . . . . .

12-17years . . . . . . . . . . . . .

18-24years . . . . . . . . . . . . .

25-34years . . . . . . . . . . . . .

3544years . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . .

65-74vears . . . . . . . . . . . . .

8.8

43.3

71.0

78.5

77.6

73.4

73.0

43.0

20.4

6.4

27.9

17.8

5.6

9.9

15.0

15.4

23.3

20.9

73.1

13.7

4.6

2.7

2.8

5.3

6.0

12.7

19.4

3.3

12.4

1.8

2.3

0.9

1.1

1.6

9.7

13.4

5.4

0.8

2.0

4.4

0.5

1.8

0.4

13.0

2.8

0.8

0.2

0.4

0.4

1.0

1.9

5.9

0.2

0.4

0.2

3.3

1.0

4.4

2.5

0.6

1.6

2.6

7.7

3.0

2.8

0.4

0.1

0.8

1.1

1.0

0.6

0.3

1.2

0.1

0.5

3.5

31
Table4. Percent distribution Of the population age 4-74 years reaching specified acuity Ievels for usual distance vision inthebetter eye, according to race,

age, andsex, with standard errors: lJnited States, 1971-1972-Con.

=

Negro

—

20/10 worse

or 20/1 5 20/20 20/25 20/30 20/40 20/50 20/70 20/1 00 20/200 20/400 than

better 2014100

.

Age and sax

Standard error

Bothsexes . . . . . . . . . .

45years . . . . . . . . . . . . .

&ll years . . . . . . . . . . . . .

12-17 years . . . . . . . . . . . .

lB-24years . . . . . . . . . . . .

2S34years, . . . . . . . . . . .

3544years . . . . . . . . . . .

4554years . . . . . . . . . . . .

55-64years . . . . . . . . . . . .

65-74years . . . . . . . . . . . .

Males . . . . . . . . . . . . .

45years . . . . . . . . . . . . .

&llyears . . . . .

12-17years . . . . . . . . . .

l&24years . .

2534years .

3544years . . . . .

45-54years . . . . . . .

5544years. . . . . . . . . . . . .

65-74years . . . . . . . . . . . .

Females . . . . . . . . . . . . .

45years . . . . . . . . . . . . .

6-n years . . . . . . . . . . . . .

12-17years . . .

lB-24years . . . . . . . . . .

25-34years . . . . . . . . . . . . .

3544years . . . . . . . . . . .

45-5-4years . . . .

55-64years . , . .

6574vears . . . . . . . . . . . .,

0.01

0.08

0.82 1.63 1.05 0.48 0.64 0.26 0.25 0.40 0.10 0.06 0.12

3.90

5.13

4.02

4.12

4.20

5.40

5.34

8.29

3.80

2.97

7.84

5.97

4.94

8.26

6.4.5

9.93

7.30

9.16

3.88

1.97

2.63

3.95

3.31

2.07

2.89

3.34

2.34

7.04

2.90

2.42

5.64

1.79

1.36

0.78

1.65

1.65

2.66

3.64

2.29

0.90

8.14

2.77

0.70

0.87

3.33

2.12

5.04

7.02

5.10

0.6B

2.26

2.28

1.11

0.92

0.77

0.77

3.18

2.81

2.33

1.02

4.70

1.90

1.88

0.97

1.25

1.59

5.90

1.61

2.54

1.13

2.47

0.36

0.66

1.56

0.52

0.72

0.37

0.50

1.50

0.23

0.52

0.48

0.83

0.94

0.62

1.20

3.83

0.40

1.39

0.63

0.82

0.18

-0.42

1.77

1.11

2.12

0.47

0.88

1.66

0.33

0.86

3.38

3.44

3.78

0.22

1.98

0.15

0.17

1.44

2.22

1.55

1.11

0.67

0.92

0.93

2.65

2.72

2.38

1.49

0.24

1.29

2.20

1.26

5.28

1.01

7,27

0.36

0.81

0.08

0.36

0.40

0.59

0.36

0.07

0.20

0.69

0.19

0,02

10.10

10.17

(3.48

:2.05

(0,09

3.78

4.55

4.67

2.94

5.42

5.26

4.23

7.38

2.49

1.57

4.80

0.28

0.82

4.39

1.75

0.02 0.57

0.35

0.74

0.17

0.45

0.09

‘1.14

0.73

1).21

——

[0.16

(0.33

3.68

4.4.3

6.37

5.45

3.30

5.15

5.41

5.B5

10.B5

4.92

3.64

4.44

5.21

2.33

3.03

5.09

4.25

8.82

4.47

7.31

3.31

2.51

1.15

0.66

1.96

1.98

4.7B

3.29

1.61

5.15

0.89

1.24

0.53

0.43

1.13

4.80

3.48

4.10

0.55

1.21

2.57

0.25

1.05

0.42

3.50

2.28

0.62

0.24

0.26

0.27

1.06

1.71

1.15

0.22

0.31

0.20

2.25

0.95

2.89

1.07

0.48

0.78

1.35

4.29

1.86

2.60

0.42

0.17

0.15

0.60

0.81

0.99

0.47

0.30

1.25

32
Table5. Percent of thepopulation age18-74 years reaching at least 20/200r no better than 20/50with usual distance visual acuity in

the better eye, by ancestry and race, with standard errors: United States, 1971-1972

Better usual monocular acuity

and ancestry

20/20 or better

Spanish, Mexican’ . . . . . . . . . . . . . . . . . .

Chinese, Japanese . . . . . . . . . . . . . . . . . .

American lndian2 . . . . . . . . . . . . . . . . . . .

All other . . . . . . . . . . . . . . . . . . . . . . .

20/50 or poorer

Spanish, Mexican l . . . . . . . . . . . . . . . . . .

Chinese, Japanese . . . . . . . . . . . . . . . . . .

American lndian2 . . . . . . . . . . . . . . . . . .

All other . . . . . . . . . . . . . . . . . . . . . . .

Total in population . . . . . . . . . . . . . . . .

Spanish, Mexican’ . . . . . . . . . . . . . . . . . .

Chinese, Japanese . . . . . . . . . . . . . . . . . .

American lndianz . . . . . . . . . . . . . . . . . .

All other . . . . . . . . . . . . . . . . . . . . . . .

Race, 1B-74 years

Percent

68.3

50.3

72.2

73.7

7.5

1.1

8.9

3.3

Ilncludespuemo Rican immigrants.

2Living off reservations.

68.3

73.6

74.1

7.6

6.2

3.0

70.0

6.0

●69.2

63.5

*52.3

86.2

*1.3

*47.7

* 0.6

Number in thousends

122,404 108,453 13,000 951

5,685 5,615 70

587 123 464

1,588 1,463 105

114,544 101,232 13,000 312

Standard error

5.05

16.44

6.07

1.40

1.76

1.66

4.57

0.35

...

...

...

...

...

5.03

6.92

1.38

1.80

4.50

0.35

...

...

...

...

...

3.0

3.5

*27.24

11.60

*32.33

3.46

●1.74

*32.33

*0.64

,.. . . .

. . . . . .

. . . . . .

. . . . . .

. . . . . .

●Figure does not meet standards of reliability or precision usually set for these reports.

33
Table 6. Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eve...-bv qeoaraDhic --- reaion.

age, r“ace,and sex,-with standard e;rors: United States, 1971-1972

20/20 or better I

20125-20140 I

20/50 or worse

Age, race,l and sex

Both sexes Percent

4-74 years . . . . . . .

All races, 4-5 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 6-11 years .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 12-17 years . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races,18-44years . . .

white . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 45-54 years .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces,55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 65-74 years . . .

white . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

73.9

36.5

72.5

42.7

5’[ .3

15.5

78.0

71.7

15.7

23.8

7

24.2

54.7 83.5

48.7 83.3

73.9 85.7

20.1 25.4

TFF

3.0 2.7 3.7 4.1

2.5 1.7 2.6 0.8

2.3 1.0 - 0.8

3.7 8.0 10.6 -

72.8

27.5

24.2

.—.—

70.0

.—

68.2

92.5

23.4

61.8

29.5

3.8

73.1

75.9

48.7

84.1

38.4

13.5

69.6

75.1

32.8

81.3

15.9

14.3

69.6

68.6

75.0

80.4

60.6

78.5

24.9

.—

22.4

46.7

25.4 2.0 I 5.0 ] 1.9 1 5.0

1.7 5.4 2.2 5.3

4.6 3.0 1.1 2.0

83.3

64.4

86.5

19.5

64.2

14.5 26.1

34.5 23.0

12.0 17.1 3.3 3.6 1.5 2.5

3.0 3.7 0.8 2.1

5.8 3.1 3.7 0.8

1.1 1.0 1.4 2.3

1.0 1.1 1.1 2.3

2.6 1.8 2.3 4.7

2.9 2.0 3.9 4.9

2.9 1.8 2.9 3.9

3.1 2.1 6.8 17.1

4.7 1.4 6.7 6.8

4.3 1.3 4.7 6.2

8.4 2.5 8.9 7.0

13.0 8.2 19.5 13.6

12.4 8.8 16.5 13.2

25.0 9.7 38.9 16.1

12.6 15.1

85.8

71.1

87.5

88.0

74.5

76.4

81.4

80.3

86.7

87.2

78.0

74.5

88.1

8 ‘1.8

85.9

82.3

68.7

84.1

11.2

23.1

14.9

16.6

11.1 15.6

14.5 30.5

11.4 12.3 12.7 13.6

85.9

85.3

65.1

83.7

79.8

67.7

11.0

22.9

11.7

20.2 z

13.0 14.0

12.4 15.5

31.0 27.4

32.4 25.8

28.8 35.6

41.6 32.2

41.7 29.6

32.6 54.5

52.5 49.9

20.7 23.5

23.2

27.6

75.0

85.4

46.6

75.0

70.3

61.0

64.7

64.4

51.7

70.3

47.3

61.0

22.1

11.5

48.7

.—

48.0

45.8

37.6

47.7

45.8

32.5

60.9

65.2

34.1

53.6

58.5

28.0

64.2

38.5

36.5

37.8

32.3

54.5 57.7

32.1

11.7

32.6

35.8

30.4

15.1

37.9

22.7

55.5

63.3

58.6

54.5

53.1 I

48.9

46.0 61.2

lRates forall races incl.de other than white and Ne9ro.
Table 6. Peraent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by geographic reqion.

age, rece, andsex, with standard errors: United States, 1971-1972-Con.

20/20 or better 20125-20140 20[50 or wocse

North- MidSouth West

North- MidSouth West

North- Mideast west

South

east

West

west east west

Age, race,’ and sax

Both sexes Standard error

4-74years . . . . . . .

All races, 4-5 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allreces,6-11 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 12-17 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allreces, 16-44years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races,4&54 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces,6574 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

3.40 I 1.83 3.70

6.18

2.80

9.16

2.50 0.66

2.35 1.97

2.38 2.11

3.23 2.29

2.99 0.35

3.20 0.58

8.06 3.92

3.90 1.92

4.30 2.27

13.44 4.15

0.99 0.54

0.84 0.47

7.75 1.82

5.43 1.26

5.64 1.14

16.06 3.32

3.39 1.79

4.66 1.73

22.64 4.87

5.72 3.88

5.64 5.08

11.24 11.96

0.21 0.58

2.14 0.82

0.92

9.48 -

1.10 2.09

1.61 2.29

0.63 2.45

1.04 0.89

0.66 0.90

2.55 0.75

0.39 0.44

0.44 0.58

1.01 2.01

1.33 1.78

0.95 1.98

3.63 14.60

2.86 2.16

3.75 2.08

3.04 5.73

1.68 4.37

2.87 5.06

5.37 4.07

1.90

2.78

1.93

1.85

2.40

1.47

3.94

10.16

2.33

0.65

0.97

0.91

16.58

2.21 T

5.90 8.S8

5.52 9.02

7.38 6.02

4.12 4.32

4.38 4.59

6.87 15.04

5.95 2.49

3.94

7.07

1.64

1.83

3.23

3.34

5.85

5.84

8.64

15.88

4.14 3.31

3.22

7.06

2.77

3.75

7.25

4.00

3.94

9.29

3.04

13.91

3.76

6.73

2.10

2.57

1.82

4.28 3.20 1.30

6.33 3.12

13.63 6.55

4.25 1.31

3.86 1.66

10.82 4.49

3.46 6.23

3.56 6.02

10.02 4.17

7.84 2.84

5.42 3.15

18.72 11.04

4.40 4.11

4.85 3.94

4.11 10.60

2.18

4.52

1.38

1.76

3.40

5.75

4.71

12.92

1.04

4.55

13.73

3.77

6.69

1.84

3.24

1.24

1.94

2.99

4.62

1.38

1.38

3.90 0.58

3.64

10.45

1.18

1.55

4.80

1.22

8.58

5.95

0.62

0.84

1.15

1.20

1.91

1.26

3.65 6.50

9.08

9.38

5.70

6.40

21.10

1.94

3.72

6.97

6.34

5.82

8.45

10.59

7.26 2.57 4.16

8.33

11.44

1.02

3.86

22.40

3.59

5.15

10.45

2.98

13.20

6.10

11.76

1.51

3.41

5.98

1.26

2.24

2.86 6.12 2.77

6.55

9.15

0,75

6.90

3.19

8.28

3.15

14.00

3.53

2.09

1Rates for aII rwes include other than white and Ne9r0.

35
Table 6. Percent of thepopulation age4-74years reaching specified acuit\, Ievelsfor usual distance vision inthebetter eye, by geographic region,

age, race, and sex, with standard errors: United States, 1971-1972–Con.

20/20 or better I20125-20/40 I20/50 or worse

Age, race,l and sex

North- Mid- South WestN(]rth- Mid-

,South West

North- Mideast west east west

South West

east west

Males

All races, 4-5 years .

Percent

‘m

68.9 63.8 48.2 77.9

=

167.7 64.9 42.6 77.6

!93.5 65.9 72.6 80.5

27.2 23.9 15.2 18.7

31.1 50.2

57.4

19.0

83.6

20.5

20.6

19.5

74.8

0.5 1.6 1.6

0.3 - 1.8

3.3 8.4 -

2.9 5.3 1.2 6.5

2.7 5.2 1.5 7.2

4.6 6.2 0.4 1.8

3.5 1.2 1.2 3.1

2.5 1.4 1.0 1.9

9.1 - 2.3 1.9

0.7 1.3 0.5 2.7

0.7 1.2 0.6 2.5

0.7 1.7 - 4.7

2.8 1.7 4.8 4.7

2.7 1.7 3.5 2.0

0.6 8.4 30.3

9.5 2.3 5.3 5.9

9.3 2.3 4.4 5.3

3.2 - 8.4 9.5

13.2 7.6 20.0 14.8

12.0 7.0 14.7 13.2

13.8 6.8 43.4 24.6

35.7

34.8

30.8

70.8

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

32.3

6.5

All races, 6-11 years . . 69.9

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

72.3

47.3

76.0

30.1

85.9

83.8

83.2

87.9

88.3

86.4

84.7

73.0

85.9

90.4

25.0

48.1

18.8

63.7

14.7 19.8

16.4 12.3

All races, 12-17 years . 81.6 14.9

——

13.6

23.2

12.9

t

10.9 6.5

70.7 5.5

11.3 6.1

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

83.9

67.7

86.7

78.9

90.4

92.6

92.0

85.8

11.9

21.1

-t

14.8 11.5

15.6 12.3

12.3 15.8

All races, 16-44 years . 87.7 11.6 8.3

white. . . . . . . . . . . . .

Negro . . . . . . . . . . . .

87.8

74.2

91.6

72.6

77.2

79.5

64.9

55.2

56.0

80.9

39.9

83.8

87.7

70.6

85.2

79.5

70.8

74.2

43.8

69.2

11.5

:25.1

7.2

25.7

-t24.6 25.1

26.0 23.8

32.3 25.9

All races, 45-54 years . . . 84.2

81.3

79.3

13.0

——

16.0

20.7

21,1

whit e. . . . . . . . . . . .

Negro . . . . . . . . . . . .

70,5

59.3

54.4

53.7

57,0

27.0

18.8

34.5

All races, 5564 years . . 49.1

47.4

73.5

,41.4 42.5 40.3 I 24.9

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

71.7

43.8

39.6

43.3

:23.3

41.7

19.1

41.9 23.0

34.6 46.7

All races, 6574 years . . 24.1 (62.7 52.5 53.0145.6

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

24.2

6.9

39.0

28.7

29.2

14.7

40.3

23.0

IB3.8 I

54.0 56.1 I

46.5

79.3 64.5 41.9 52.4

lRates forall races include other than white and Ne9r0.

36
Table 6. Percent of thepopulation age4-74years reaching spmified muiwlevels forusual dismnce vision inthebetier we. bvqemra~hicreaion.

age, race, and sex, wi;h standard errors: United States, 1971-1972—Con.

---- -.

20/20 or better 20/25-20140 20150 or worse

North- MidSouth WestNorth- MidSouth West

North- MidSouth

east west east

West

west east west

Age, race,l and sex

Males Standard error

4.61

5.09

7.27

6.09

6.67

2.19

1.93

1.06

5.24

1.54

1.59

21.47

5.67

9.17 5.26

12.73 5.87

14.04 7.27

2.98 5.29

4.82 5.64

4.67 3.04

2.43 1.87

3.05 1.41

1.30 5.48

1.49 1.60

2.03 0.65

6.31 13.05

2.90 4.69

9.22 4.40

13.43 30.38

4.83 5.06

6.37 4.43

8.34 24.15

4.48 4.82

4.92 5.29

6.09 15.95

Allraces,4-5 years . . . . 8.71 9.87 10.60 0.33 I 1.60 I 1.73

8.82 10.10 12.73

9.47 23.31 12.07

5.49 4.37 2.57

6.74 4.90 4.00

16.16 10.66 4.55

6.31 1.99 2.31

6.20 2.94 2.50

17.19 12.36 1.83

5.73 1.73 1.30

5.71 2.12 1.45

24.73 9.11 6.31

4.32 7.20 5.92

8.71

8.82

9.47

5.T7

5.96

16.86

4.99

4.59

16.54

5.75

5.82

24.29

5.62

9.94

10.04

21.32

3.73

3.95

9.37

1.05

2.25

12.36

1.16

1.48

10.19

8.24

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

0.31

8.24 9.08

1.96

0.69

1.21

4.41

1.97

2.20

6.51

0.79

0.73

0.99

2.07

2.03

2.45

6.55

Allraces,6-11 years . . . 1.20 3.84

1.54

0.54

4.34

2.22

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 12-17 years . . . 1.57 ] 0.86 / 1.09

white.............

Negro . . . . . . . . . . . . 1.47 1.61

Allraces,l&44years . . . 0.83 0.49 0.72

m3

white. . . . . . . . . . . . .

Negro . . . . . . . . . . . .

1.55 I

All races, 45-54 years . . . 3.13 1.59

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

5.24

41.05

6.28 10.93

13.22 9.90

5.42

30.05

7.60

6.42

41.05

6.91

7.42

14.49

6.02

2.13

5.59

1.67 2.14

5.13 5.96

1.53

25.36

All races, 55-64 years . . . 7.47 6.81 I 6.45 2.44 I 3.81 I 3.86

2.41 3.76

8.80

3.64

7.10

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

6.50

17.92

7.01

34.69

7.72

13.88

6.69

30.85

4.81

5.09

8.20

4.30

17.57

5.75

5.65

9.26

6.28

16.59

5.53

6.06

11.92

5.38

2.16

6.67

6.29

7.61

All races, 65-74 years . . . 4.45

4.80

8.83

3.10

3.72

11.49

3.34

2.98

6.00

3.73

3.53

4.65

2.35 3.31

3.93

8.40

white. . . . . . . . . . . . .

Negro . . . . . . . . . . . .

3.15

7.96

lRates f~rall races include other than white and Ne9r0.

37
Table 6. Percent of thepopulation age4-74years re~hing W~ified acuiWlevels forusual distance vision inthebetter eye, by geographic region,

age, race, and sex, with standard

20/20 or better

I 1 I

vclrs: United States, 1971-1972—Con.

=

20/25-20/40 20/50 or worse

—

Age, race,l and sex

North- 1

Mid- 1

South I

West I

North- 1

Mideast I

South I

West

west east west

North- 1

Mid- 1

South IWest

east west

1 1 I — I 1 I I I I I

Females Percent

All races, 4-5 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 6-11 years .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 12-17 years . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 18-44yaars . .

White . . . . . . . . . . . . .

Negro . . . . . . .

All races, 45-54 years . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 65-74 years .

white.. . . . . .

Negro . . . . . . . . . .

24.6

27.1

2.8

77.0

37.3 31.3 59.7 64.7 4.4 3.0 I 4.0

40.3

12.3

71.2

11.6

11.8

10.7

64.0

71.0

-—

68.6

92.2

22.1

88.4

88.2

89.3

32.7

32.5

37.9

26.3

24.2

47.7

15.4

42.5

4.9

68.8

55.6

84.8

26.3

59.7

75.0

26.1

4.3

5.0

0.9

1.9 -

10.3 12.7

4.9 2.7 3.3

80.3

50.2

87.1

88.1

77.0

87.3

74.5

34.3

76.7

76.1

81.7

82.9

82.6

44.2

85.1

87.9

78.1

86.9

64.1

59.9

71.8

73.6

52.3

82.6

19.3

45.2

9.8

8.3

23.0

11.2

20.0

64.5

17.3

14.3

54.1

13.1

0.4

4.6

3.1 I

5.5 3.1

1.2 1.7

6.0 1.8

6.0 0.6

6.1 4.9

0,8 2.2

1.0 1.6

1.9 4.2

2.3 3.1

3.4

2.2

1.9

.—

2.2

2.0

17.9

12.2

16.3

11.5

17.0

10.9

3.6

1.5

88.1

74.6

70.3

70.0

88.6

44.8

82.7

83.7

71.1

69.3

75.1

68.0

87.6

83.4

60.1

60.0

70.1

49.0

82.3

79.9

64.8

66.8

51.8

54.6

10.6

21.9

26.7

-—

26.9

6.7

53.8

.—

51.4

77.4

47.9

16.3

14.4

26.6

10.8

12.4

36.8

15.5

15.3

29.7

27.7

48.2

37.9

1.3

3.5

3.0

2.2

4.8

5.5

28.8

21.4

31.7

37.6

25.0

42.9

3.1

4.7

1.4

1.9 2.4

3.5 4,9

0.3 8.1

5.6

7.5

6.8

5.9

12.7

47.9

7.0

39.3

66.7

58.2

30.1

53.4

59.9

28.8

58.5

36.1

33.9

33.3

38.2

61.3

41.7

30.7

52.0

34.7

58.0

53.4

0.7

15.6

12.8

4.9

3.6 9.4

8.6 19.2

10.0 17.6

11.4 35.1

38.5

15.3

28.1

39.9

31.2

15.4

36.0

22.4

48.8

51.6

61.9

48.7

51.2

49.5

50.9

67.8

12.7

33.1

13.1

9.8

lRate~ f~rall races include other than white and Negro

38
Table6. Percent of thepwulation ~e4-74yeam reaching spwified muitylevels forusual diswncevision inthebetter eye, by geographic region,

age, race, andsex, with standard errors: United States, 1971 -1972–Con.

20/20 or better I

20125-20/40 I20/50 or worse

Age, race, 1 and sex

North- MidSouth WestNorth- Mideast west

South West

east west

North- 1

Mid- 1

South West

east west

Females

All races, 4-5 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces,6-11 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 12-17 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 18-44years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 45-54 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 6&74 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Standard error

3.73

4.45

2.68

3.23

3.56

3.05R

2.49 3.76 -

2.16 - -

21.61 10.45

2.60 2.22 0.68

3.00 3.16 0.59

2.00 1.11 2.91

13.39

12.63

24.80

4.04

13.38

16.44

13.86

1.92 2.42 0.79

5.15 4.95 6.70 1.96 5.37

7.49 19.55 10.04 19.16 9.83

6.45 5.40 5.33 6.93 4.76

3.33

18.69

5.95

5.51

9.73

4.84

1.86

19.91

0.45

3.71

6.61 2.22 1.14 I 1.46 I 1.27

7.08 6.19 4.89 7.62

11.62 5.39 8.03 14.54

5.39

11.62

6.62

4.09

2.88

3.08

2.60

7.96

4.82

6.60

1.93

2.46

3.07

7.14

7.15

14.54

2.58 1.24 0.56 1.40

2.11 3.70 -

3.27 0.44 0.90 0.28

2.64

6.70

1.33

1.47

8.66

0.70

0.65

2.73

1 I

0.71 0.92 0.25

1.03 1.85 2.46

5.25 1.87 0.87 2.80 I7.43 I

6.74 I8.53 5.56 8.14 2.05

1.98 1.49 2.87

2.62 3.31

0.34 3.40 2.34

4.64 8.44 8.35 9.08 5.33

7.25 9.97 12.14 16.29 4.81

9.72 6.25 5.37 7.55 8.91

9.26

11.56

6.35

8.69

10.09

4.63

8.68

16.29

2.03

4.73

8.00 1.26

7.83 7.11 10.55 6.22 7.12

5.57 24.13 13.87 24.48 10.33

4.73 5.92 1.41 2.99 3.36

7.11

26.91

7.71

7.53

17.92

3.97

7.46

32.17

0.83

13.77

5.77 2.46

3.07 5.44 5.22

7.22 2.19 3.52 3.48 5.90

5.56 I

5.18 I

2.83 I

2.05 I

3.33

6.90 19.38 9.51 11.78 18.59

7.71

19.41

6.88

6.04

6.65

14.27

4.52

16.35

4.41 4.67 6.41

5.63 5.97 4.70

lRatesfOr allraces include other than white and Negro.

39
Table7. Percent of the copulation age4-74vears reaching specified acuity Ievels for usual distance vision in the better eye, by size of place of

residence, age, race, and;ex, with standard errors: United States, 1971-1972

20/20 or better 20150 or worsa

=:

Standard error

1.73 1.65 1.16 0.37 0.76 0.35

~

4.11 13.17 4.49 0.98 4.27 0.52

Age, race,l end sex Nonurbanized

Rural

Both sexes

4-74 years . . . . . .

All races, 4-5 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

All races, 6-11 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 12-17 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allracas, 18-44years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces,45454y ears . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Ail races, 55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

All races, 65-74 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Percent

T

73.1 3.5

26.8 2.1

28.7 1.9

6.1 3.4

73.9 3.8

+

3.6 3.0

5.5 0.5

72.4

35.4

73.2

28.5

4.29 16.46 4.90 1.13 1.70

4.05 15.14 3.66 2.42 24.29 7.53

2.44 4.86 2.64 1.14 0.80 1.79

39.4

14.0

7i.5

30.1

21.3

73.1

1.7

22.2 5.9

2.3 3.4

2.46 5.67 3.16 1.48 0.98 2.03

6.43 14.59 7.28 1.26 1.24 1.10

2.69 3.26 2.39 0.68 1.28 1.13

76.0

51.4

82.2

75.0

59.9

64.9

74.7 4.1

65.4 2.7

63.0 2.8

2.4

1.8

3.6

1.2

2.1 2.8

83.4

77.4

84.7

88.1

65.7

86.4

83.4 2.6

78.5 1.9

86.8 1.8

86.8 1.7

86.3 2.7

70.3 2.8

72.2 2.8

48.5 2.6

54.9 3.6

55.3 3.8

43.6 8.3

29.7 15.9

0.5

16.9

2.9

2.8

2.64 3.30

5.72 16.93

2.79 0.99 0.59

11.16 0.60 11.87

1.16

2.05

2.2 I 0.8 1.55 I 1.51 0.34

1.81

I

1.70

3.05 11.37

85.6

79.8

71.2

87.2

77.6

72.7

1.9

6.6

0.8

1.1 0.56

-t-t

5.37 0.74 2.54

5.63 0.66 2.87

11.38 1.14 -

5.90 0.90 2.86

+

4.01 4.94

4.44 6.89

-=-t- 4.33 22.18

3.3 3.9

3.7 2.6

18.9

1.25

71.1

72.1

54.6

72.4

75.6

54.7

10.52

4.9 5.8 2.95 I 4.34 2.06

3.02 4.63 6.26 0.97 2.80 2.41

10.65 20.28 13.61 2.27 4.93 6.86

3.31 4.68 3.35 2.39 3.61 2.72

3.42 5.04 3.04 2.93 4.30 2.69

5.73 12.97 7.06 6.30 20.41 5.19

55.5

49.0

29.4

54.5

59.5

34.0

4.5

6.2

4.8

15.2

13.1 I 11.5

29.8

25.0

35.7

14.9

30.9 I

16.0

11.9 25.3

12.9 I11.2

34.0 30.6

lTOtal~ include races other than whita and Negro.

40
Table7. Percent of the population age 4-74 years reaching specified acuity Ievelsfor usual distance vision inthebatter eye, by size of place of

residence, age, race, andsex, with standard errors: United States, 1971-1972–Con.

20/20 or batter 20150 or worse 20120 or better 20/50 or worse

Age, race,l and sex Non- Non- Non- NonUrban urban- Rural Urban urban- Rural Urban urban- Rural Urban urban- Rural

ized ized ized ized

Males Percent Standard error

I

74.4 3.1 3.1 3.2 1.72 3.59

28.5 0.3 6.7 - 5.01 12.39

30.2 0.2 3.4 - 5.51 15.22

8.6 1.1 19.9 - 9.19 25.79

75.2 4.4 3.8 3.1 3.95 6.01

74.7 4.6 4.1 3.6 4.70 7.23

76.7 3.4 1.9 - 8.68 19.32

87.2 2.1 2.0 2.7 2.24 6.20

86.8 1.3 - 2.8 2.00 5.16

68.3 1.9 29.0 2.3 6.97 36.93

86.9 1.6 0.4 0.9 2.10 4.01

4-74years . . . . . . .

FF

76.0 73.4

All races, 4-5 years . . . . 44.9 28.6

whit e . . . . . . . . . . . . 47.2 27.4

Negro . . . . . . . . . . . . . 20.5 33.2

1.40 0.48 0.86 0.45

8.55 0.21 4.23

0.19

1.12

3.33

19.42

9.%

5.88

Allraces, &ll years . . . . 2.90

tt

74.5 75.6

white . . . . . . . . . . . . . 76.6 76.6

N&J-o . . . . . . . . . . . . . 64.7 65.5

3.86

4.56

5.92

1.07

1.40

1.61

2.06

2.28

2.30

3.32

Allraces, 12-17 years . . .

t-t

86.4 85.6

~ite . . . . . . . . . . . . . 88.3 91.0

Negro . . . . . . . . . . . . . 80.6 50.9

2.31 1.11 2.31 1.05

0.87

1.11 31.22

1.12

2.20

2.71

3.75

Allraces, 18-44 years . . .

1+

86.6 86.4

WMte . . . . . . . . . . . . . s8.0 86.8

Negro . . . . . . . . . . . . . 77.4 81.4

2.05 0.59 0.28 0.59

w

86.6 1.7 0.1 0.9

68.3 0.8 3.6 0.8

75.6 2.6 1.8 4.4

79.2 2.9 2.1 1.8

38.4 0.3 - 31.1

53.5 3.9 5.3 6.7

2.54 4.78

5.46 28.95

0.70

0.61

0.14

5;25

0.61

0.88

2.12

4.66

Allraces,4H4y ears . . .

tt

75.5 73.0

White . . . . . . . . . . . . . 76.4 73.5

Negro . . . . . . . . . . . . . 68.3 69.7

t

4.25 10.05

3.92 14.66

10.79 27.01

5.91

5.50

11.80

1.15

1.30

0.45

2.15 2.44

1.44

20.16

2.80

t+

Allrwes,65-64 years . . . 58.4 51.2

~ite . . . . . . . . . . . . . 56.3 50.9

Negro . . . . . . . . . . . . . 67.5 57.4

4.13 I 7.58 8.OU 2.00 4.80 3.66

54.2 4.6 4.7 6.8 4.84 8.17

42.2 3.9 12.2 10.9 10.74 32.03

8.28

17.27

1.68

2.06

4.91 3.85

13.73 11.42

Aliraces,65.74years . . .

H28.2 32.6

mite . . . . . . . . . . . . . 28.9 34.7

Negro . . . . . . . . . . . . . 19.6 17.9

31.2 I 12.9 I 17.7 I 13.1 I 4.o7 I 3.28 5.42 2.97 6.47 I 2.58

3.49 I

8.07 2.78

10.17 20.43 7.34

32.6 I

11.6

I

17.3

I

11.5 I

4.16 5.12

7.3 29.1 32.6 42.3 6.08 18.01

5.24

4.63

1To~IS include races other than white and Ne8rc

41

.
Table7. Percent of the population age4-74 years reaching specified acuity leval.s for usual distance vision in the better eye, by size of piactsof

residence, aga, race, andsex, with standard errors: United States, 1971 -1972 –Con.

Age, race,l and sex

Females

4-74year3 . . . . . .

All races, 4-5 years . . . .

Whita . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces,6-11 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

All races, 12-17 years . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 18-44 years . .

white . . . . . . . . . . . . .

Nag.. . . . . . . . . . . .

All races, 45-54 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces,55-84 years .

white . . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces,65-74 years . . .

white . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Percent

69.1

26.2

30.7

11.0

68.7

75.3

39.0

77.3

77.7

73.6

83.0

83.2

81.3

67.6

66.5

74.9

51.5

73.1 71.8 3.9 4.1

=

28.4 25.0 3.9 4.1

32.9 27.0 3.7 -

5.2 3.3 4.4 25.3

69.7 72.5 3.3 0.3

72.7 74.7 3.6 -

W?.6 53.0 2.0 1.6

84.3 79.1 3.7 2.1

85.7 80.3 4.1 1.0

73.1 70.4 2.0 10.9

86.4 86.8 1.9 3.8

87.6 87.1 1.6 3.4

74.2 82.7 3.9 9.3

72.4 65.2 3.0 5.1

71.2 65.6 2.8 5.4

94.0 60.5 4.1

58.0 56.3 3.4 4.6

2.8

=

1.0

12.5

3.6

3.7

2.4

3.0

3.0

3.2

0.7

0.6

1.4

3.4

3.4

4.4

4.8

53.3

38.3

30.2

30.4

28.7

57.9 56.4 3.2 4.4

61.5 46.7 10.9

2.9

21.7

!&la&&E

Standard error

1.95 1.54 1.71 0.42 0.77 0,51

*

5.13 17.72 8.51 1.97 5.43 11,11

—

6.82 20.75 9.25 2.36 -

6.29 5.20 3.37 3.36 35.08 14.38

2.19 8.99 3.13 1.44 0.26 2,15

—

2.67 10.95 4.13 1.85 - 2,44

7.04 20.80 9.61 1.47 1.60 1.95

4.63 4.94 4.05 1.10 1.42 1.45

4.97 5.66 4.45 1.38 1.10 ‘1.51

6.84 15.44 18.18 0.78 9.59 2.45

4.85 6.38 6.59 1.14 3.79 ‘1.53

—

6.13 6.84 7.24 1.30 3.88 ‘1.85

5.50 25.62 17.21 1.76 - 4.57

3.70 8.87 5.92 1.16 2.52 ‘1.84

—

4.04 9.21 6.37 1.49 2.44 2.93

13.39 32.31 19.86 4.08 - 13.74

lTotais include racas other than white and Negro.

42
Table8. Percent of thepopulation age4-74 years reaching specified acuity levels forusual distance vision inthebetter eye, by family

income, age, race, andsex, with standard errors: United States, 1971-1972

Age, race,’ and sex

Both sexes

4-74years . . . . . . . .

All races, 4-5 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,6-11 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, 12-17 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, 18-44 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,4554 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, 55-64 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,6&74years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

20120 or better 20125-20/40 20/50 or worse

Under $5,()(30. $’:;? Under $5,000- $’:;?

$5,000 $9,999 $5,000 $9,999

Under $5,000 $’:;@Jo

over

$5,000 $9,999

over over

Percent

60.1 70.5 79.5 32.3 26.2 18.8 7.6 3.3 1.7

25.0 26.5 37.1 71.8 73.0 62.1 3.1 0.5 0.9

28.3 29.3 38.2 71.7 70.1 60.9 0.5 0.9

19.7 7.2 5.3 71.9 92.2 94.7 8.4 0.6

67.0 65.4 79.5 27.4 31.9 17.0 5.6 2.7 3.5

71.8 68.9 79.9 21.0 28.2 16.5 7.2 2.9 3.5

57.4 45.6 69.2 39.5 52.7 28.7 3.1 1.7 2.0

75.3 80.5 86.3 20.2 17.6 11.3 4.5 1.9 2.4

72.2 81.8 87.1 22.1 16.2 11.0 5.7 1.9 1.9

78.8 73.9 81.6 18.3 24.2 11.8 2.9 2.0 6.7

83.3 84.2 88.2 13.9 14.0 11.0 2.8 1.9 0.8

84.1 84.3 88.8 13.5 14.0 10.3 2.4 1.7 0.9

82.0 83.6 75.9 14.0 73.7 23.9 3.9 2.7 0.2

56.6 64.1 78.1 32.2 31.5 20.9 11.2 4.4 1.0

53.6 64.9 78.0 37.0 30.2 21.0 9.3 4.9 1.0

63.6 58.7 80.2 20.3 40.1 19.5 16.1 1.2 0.3

45.7 56.4 59.5 45.9 37.0 39.5 8.4 6.6 1.1

46,2 57.3 58.5 45.7 36.7 40.5 8.1 6.0 1.0

43.3 57.5 83.1 46.6 37.4 13.5 10.0 5.1 3.4

29.1 37.2 35.5 54.2 50.8 55.8 16.6 12.0 8.8

30.7 37.6 36.3 54.3 51.3 55.1 15.0 11.1 8.6

17.9 29.4 3.3 54.7 41.6 81.8 27.4 29.0 14.9

lTotal~ include races other than white and Negrch

43
9.+

Table8. Percent of the population age 4-74 years reaching specified acuity levels forusual distance vision inthebetter eye, by family

income, age, race, andsex, with standard errors: United States, 1971-1972—Con.

Age, race,’ and sex

20/20 or better I20/25-20/40 I20160 or worse

$10,000

and

over

$10,000

and

over

Under $5,000-

$5,000 $9,999

Under

$5,000

$5,000-

$9,999

Both sexes

4-74 years . . . . . . . .

All races, 4-5 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,6-11 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races, 12-17 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races, 18-44 years . . . .

White . . . . . . . . . . . . . .

Negro , . . . . . . . . . . . . .

All races,45-54 years . , . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . , . . . .

Allraces,55-64years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,65-74years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Stendard error

1.71 0.88 0.43

3.69 3.49 0.47

2.05 I 1.29 1.71 1.57 1.18 0.26

7.42 I 4.62 3.90 8.85 4.64 0.66

+

11.96 4.98

7.60 3.14

4.33 3.54

5.66 3.97

5.34 7.94

5.91 3.15

3.78

3.97

2.59

—.

2.85

14.17

1.39

11.96

11.62

2.90

3.57

4.97

5.23

4.97

3.31

3.55

3.85

7.86

2.84

3.58 -

3.97 8.56

0.53

0.62

0.69

1.24

t

2.39 2.89

2.65 4.49

13.81 1.04

0.97

1.13

0.87

1.33

2.58

1.52 I 2.06 0.76 0.67

1.60 3.04

6.84 2.14

0.86

1.03

1.50

8.78

1.76

7.82

4.43

1.99

2.61

3.33

4.54

+

8.74 3.71

4.22 8.64

2.10 1.45

2.41 1.73

3.69 3.11

5.44 4.23

3.31

8.82

1.18

0.59

5.64

0.35

t

1.65 0.63

1.61 0.82

7.55 1.11

0.41

1.73

7.47

3.90

1.54

2.88

3.94

0.42

1.50

0.37

0.15

0.56

t

3.99 3.37

4.18 4.70

7.58 6.60

1.76

9.23 4.39

8.35 10.76

7.20 4.18

4.08

7.55

4.64

3.93

11.02

3.21

1.98

0.99

7.08

4.37

6.08

0.60

0.39

4.88 I 2.77 1.59 1.02

7.07 4.59

11.08 14.94

1.94 2.85

4.32

20.79

4.95

6.37

10.94

1.85

3.44

13.97

3.64

4.65 3.39 2.13

15.42 3.29 3.32

5.86 2.21 2.43

1.06

6.77

2.22

6.23 I

2.42 2.77

11.00 4.04 13.24

2.01 3.07

5.10 10.68

5.30

5.51

1.77

4.81

4.00

12.70

2.23

10.97

lTotals include races other than white and Ne9r~.

44
Table8. Percent of thepopulation age 4-74 years reaching specified acuity levels forusuaI distance vision inthebetter eye, by family

income, age, race, andsex, with standard errors: United States, 1971 -1972 —Con.

Age, race,’ and sex

Males

4-74years . . . . . . . .

All races, 4-5 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,6-11 years . . . . .

White . . . . . . . . . . . . . .

Negro, . . . . . . . . . . . . .

Allraces,12-17years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, l&44years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,45-54 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,55-64 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Ailraces,65-74 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

20/20 or better 20/25-20140 20150 or worse

Under $5,000- $10,000 Under $5,000- $’:;00 Under $5,000- $’:;00

$5,000 $9,999 and $5,000 $9,999 $5,000 $9,999

over over over

Percent

64.4 I 72.1

T

26.9 31.6

28.8 33.2

24.0 14.0

68.3 67.7

69.1 69.4

65.3 56.9

82.6 88.2

83.6 88.8

80.3 83.8

89.1 85.1

90.9 84.7

85.4 87.5

60.1 67.2

62.1 69.1

57.6 59.1

47.0 53.9

4- 47.4 54.4

44.5 61.0

27.8 34.1

28.8 35.2

18.8 6.8

81.1 26.8 24.7 17.5 8.9 3.1 1.3

42.2 69.8 67.4 57.7 3.3 1.0 0.2

42.3 71.2 65.8 57.5 1.0 0.2

16.3 67.8 64.4 83.7 8.2 1.7

81.9 24.0 29.1 15.3 7.7 3.1 2.8

81.5 20.6 27.4 15.5 10.3 3.2 2.9

88.4 31.4 40.6 11.6 3.3 2.5

88.0 12.6 10.8 10.5 4.9 1.1 1.4

89.3 9.4 10.1 10.3 7.0 1.1 0.4

86.0 17.5 15.2 5.6 2.2 1.0 8.4

88.3 9.3 13.4 10.7 1.6 1.6 1.0

89.5 7.7 13.6 9.4 1.3 1.7 1.1

65.3 12.3 11.7 34.7 2.3 0.7

81.7 17.3 28.6 18.1 22.5 4.1 0.2

82.3 15.9 26.0 17.6 22.0 4.9 0.1

63.4 19.2 40.0 35.5 23.3 0.9 1.1

62.3 38.4 40.4 35.8 14.6 5.8 1.9

61.4 37.0 39.7 36.7 15.6 5.9 1.9

92.0 46.2 34.1 3.8 9.3 4.9 4.2

39.4 54.9 51.4 54.5 17.3 14.5 6.2

40.7 57.0 51.0 53.3 14.3 13.8 6.0

4.9 45.6 63.6 86.3 35.6 29.6 8.8

lTOta[s include races other than white and Ne9r0.

45
Table8. Percent of the population age 4-74 years reaching specified acuity levels forusual dismnce vision inthebetier eye, by family

income, age, race, and sex, with standarcl errore: United States, 1971-1972–Con.

20/20 or better 20/25-20/40 20/50 or worse

Age, race,l and sex

Under $5,000- $’:;y Under $5,000- $’:;00

$5,000 $9,999

Under $5,000- $’:;y

$5,000 $9999

over over

$5,000 $9,999

over

Males Standard error

4-74years . . . . . . . .

F

2.43

All races, 4-5 years . . . . . 7.71

2.10

9.55

1.63

8.00

1.97 1.04 0.64 0.33

5.68 3.59 0.89 0.19

5.85 0.96 0.20

15.81 8.56 1.68

White . . . . . . . . . . . . . .r

13.02

Negro . . . . . . . . . . . . . . 11.68

8.88 5.83

6.48 15.81

13.02

13.49

8.90

6.75

Allraces,6-11 years . . . . . 4.67

t

6.40

White . . . . . . . . . . . . . . 8.19

Negro . . . . . . . . . . . . . . 6.86

t

5.09 4.03

5.20 4.16

15.56 12.68

4.49 3.79 I 4.55 ] 1.43 I 1.40

3.89

12.68

6.61

1.51

5.26 1.62 I 1.48

6.55

4.75

15.18

3.05

1.71 I

Allracesr 12-17 years . . . .

F

4.94

White . . . . . . . . . . . . . . 6.63

Negro . . . . . . . . . . . . . . 5.95

t

3.03 1.55

—

3.33 1.51

6.70 9.64

4.48 1.20 2.77

t0.81 0.94

0.94 0.43

0.91 9.60

5.98

6.81

3.28

6.81

2.35

1.34

2.58

4.72

1.62

All races, 18-44 years . . . .

F

3.32

White . . . . . . . . . . . . . . 3.44

Negro . . . . . . . . . . . . . . 8.04

t

2.66 2.49

.

2.$8 2.50

6.34 12.41

3.13 2.29 0.98 0.73 1 0.61

3.40

7.43

2.58

5.92

4.21

2.25 1.10 0.81 0.65

12.41 1.65 0.87

All races,45-54 years . . . . 4.72 7.60 2.43 0.15

t--

9.92

white . . . . . . . . . . . . . . 16.42

Negro . . . . . . . . . . . . . . 11.83

3.92 I 4.77 6.27

4.55 4.53

14.76 26.16

7.10

9.81

4.43

14.76

4.46

4.47 I

15.93 2.95 I

0.16

26.40 11.85 1.01 1.18

All races, 5564 years . . . . 4.77 6.83 3.23 I 1.85

t

9.79

White . . . . . . . . . . . . . . 8.48

Negro . . . . . . . . . . . . . . 24.30

5.25 ] 4.91 6.91

5.40 5.00

19.58 20.24

6.99

17.18

4.67

19.73

5.40

4.87 7.64 3.52 1.90

8.81 8.93 5.39 14.33

All races, 65-74 years . . . . 1 3.14 3.74 ] 5.24 3.82 6.05 I 2.34 I 4.97 I 2.58

3.90 I

5.55

5.22 7.09

6.33 2.45 4.84 I

2.40

17.97 6.32 20.40 14.20

white . . . . . . . . . . . . . .

I

3.17

Negro . . . . . . . . . . . . . . 4.89

3.73

6.02

5.82

18.17

lTotals include races other than white an

46
Table8. Percent of thepopulation age 4-74 years reaching specified acuiWlevels forusuai distance vision inthebetier eye, by family

income, age, race, andsex, with standard errors: United States, 1971-1972—Con.

Age, race,’ and sex

Females —.

4-74years . . . . . . . .

All races, 4-5 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allracesr 6-11 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, 12-17 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,18-44years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces,4S54years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

AHraces,5%64years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allracas,65-74years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

20/20 or better 20/25-20/40 20150 or worse

Under $5,000- $’:;00 Under $5,000- $’:;y Under $5,000-

$10,000

$5,000 $9,999 $5,000 $9,999 $5,000 $9,999

and

over over over

Percent

57.0 69.0 77.8 36.3 27.6 20.2 6.7 3.4 $ 2.0

23.5 20.9 31.5 73.6 79.1 66.8 2.9 1.7

27.9 24.6 33.5 72.1 75.4 64.7 - 1.8

15.2 3.5 76.2 96.5 100.0 8.6

65.1 63.2 77.2 32.1 34.5 18.7 2.8 2.2 4.1

75.6 68.5 78.4 21.5 29.0 17.5 2.9 2.5 4.1

47.9 37.3 54.1 49.3 61.6 42.3 2.8 1,2 3.6

68.9 73.5 84.3 26.9 23.8 12.2 4.2 2.7 3.5

62.8 74.9 84.7 32.5 22.3 11.8 4.7 2.8 3.5

77.2 68.0 74.7 19.2 29.5 21.4 3.6 2.5 3.9

79.3 83.3 88.1 17.1 14.5 11.3 3.6 2.2 0.6

79.0 83.9 88.1 17.8 14.4 11.2 3.2 1.8 0.7

80.0 80.3 85.6 15.1 15.3 14.1 4.9 4.3 0.3

54.9 61.4 73.8 39.1 33.9 24.2 6.0 4.7 2.0

50.8 61.7 72.7 44.1 33.4 25.2 5.1 4.9 2.1

69.7 57.9 87.1 21,4 40.2 12.9 8.9 1.9

45.2 58.9 56.1 49.2 33.5 43.9 5.7 7.5

45.7 60.3 54.9 49.7 33.6 45.1 4.6 6.1

42.9 53.8 46.0 46.8 40.9 54.0 10.3 5.2

30.0 40.0 32.0 53.8 50.2 56.9 16.2 9.s 11.1

31.9 39.8 32.5 52.5 51.5 56.7 15.5 8.7 10.8

17.2 44.4 61.4 27.0 72.7 21.4 28.6 27.3

lTOtals include races other than white and Negro.

47
Table8. Percent of the population age4-74yeam reaching specified acuity levels forusual distance vision inthebe~er eye, byifamily

income, age, race, andsex, with standard errors: United States, 1971-1972-Con.

20/20 or better 20/25-20/40 20150 or worse

Under $5,000-

$10,000

Under $5,000-

$10,000

Undar $5,000- $’:doo

$5,000 $9,999

and

$5,000 $9,999

and

over

$5,000 $8,999

over O\fer

Age, racer’ and sex

Females

474 years . . . . . . . .

All races, 4-5 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races, 6-11 years . . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races, 12-17 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races, 18-44 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races,45-54years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

All races,55-64years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Allraces, 65-74 years . . . .

White . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . .

Standard error

=++&=++

2.88

T

1.42 1.92

6.12 7.37

7.62 7.57

2.32

4.21 3.23

+=

0.47 0.41

9.71 1.34

13.42

9.90

5.82

6.12

7.08

7.58

13.42

14.95

7.62 7.27

2.32

4.08 2.82

9.17

1.46

6.01

7.35

6.76

1.48 1.42 1.98

4.84 3.58

8.24 19.08

4.62 3.03

4.43 3.27

8.19 19.11

2.79

1.30

1.68

0.90

2.07

6.81

7.05 4.37 I 3.22 2.71 1.27 1.01

11.01

4.92

2.75

3.35

3.39

8.02 +

6.49 3.24

12.44 16.00

1.63 1.89

1.65 1.92

3.54 7.73

6.35 5.34

10.77

3.85

6.19 3.45

12.55 15.98

3.88

2.99

1.53

1.58

1.06

3.11

2.36 1.65 I 1.91 0.82 0.65 0,34

3.40

3.44

1.85 1.94

3.98 7.81

0.92

2.04

0.66

2.42

0.36

0.27

7.22 6.37 I 5.52 2.47 2.41 1.22

9.28 7.14 6.39 3.59

8.25 18.53 10.35 4.86

7.50 5.35 9.32 1.80

2.54 1.33

1.92

2.74

11.13

11.15

8.26

7.03 6.19

17.84 10.35

4.66 9.32

5.04 9.08

16.26 34.13

4.17 6.11

7.25 6.16 9.08 2.30

15.86 14.43 34.71 3.73

3.07 4.70 7.87 2.97

4.14

5.12

2.03 3.51

8.28

14.90

2.06

4.36 6.32

16.91

2.20 I

3.66

18.13 24.06

2.48

6.17

3.48 4.88 8.05 3.12

5.35 10.24 35.49 4.49

1Totals include races other than white and Ne9r0.

48
Table9. Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

education of head of household, age, race, and sex, with standard errors: United States, 1971-1972

Age, race,l and sex

20/20 or batter acuity

3

20/50 or worse acuity

Both sexes

4-74 years . . . . . . . . . . . . . . . . .

Allraces,4-5 years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,6-ll years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces, 12-17years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,18-44years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,4%54years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,55-64years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allracesr65-74years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Percent

74.3 79.9 20.9 5.8 2.9 1.7

35.4 31.1 - 3.2 0.7 2.9

36.5 I 61.4

-1 18.2

38.0

16.2

33.2

4.7

0.3

13.3 5.1

18.7 3.2

16.8

40.7 70.8 72.2 76.0 39.5

42.3

53.2

1.7 3.2 3.8

38.0 74.9

60.0

49.1 79.8

75.0

54.7

78.2

43.6

1.6

2.0

3.3

2.3

4.1

83.1 86.9 3.2 3.4 I

0.9

83.9

79.0

46.2 81.7

100.0 73.5

59.5 78.3

87.9

79.4

3.1 3.0 1.0

3.3 4.1

84.8 90.8 12.4 2.4 1.9 0.5

85.2 91.8

81.6 77.3

16.1 +-l 2,3 1.7 0.4

2.6 3.1 2.0

6.7 2.5 0.6

6.8 2.5 0.5

6.1 2.6 3.3

9.0 2.3 2.5

65.0 77.3

64.2 81.7

9.7 63.4 72.2 I 80.7 I 24.7

11.7 61.2

71.8

67.6 42.3

73.0 80.9

63.5 75.5

11.4

88.0

63.3 \ 59.9 I 10.6

62.5

37.7

59.4

75.5

4.3

25.5

8.1

9.0

2.3

10.2

2.9 -L68.9 39.2

67.9 49.8

22.2 26.5

14.9 26.6

18.8 15.5

31.6 40.1 31.0 16.0 12.7 9.8

29.9

36.1

37.7

9.9

31.3

35.2

15.0

31.7

13.6

22.0

11.0

9.4

lTOtals include races other than white and Negro.

49
Table9. Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

education of head of household, age, race, andsex, with standerd errors: United States, 1971 -1972–Con.

Age, race,l and sex

Both sexes

4-74 years . . . . . . .

All races, 4-5 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces,6-11 years . . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 12-17 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 18-44 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces,45-54 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 55-64 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

Allraces, 65-74 years . . .

White . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. ..!... . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

. . . . . . . . . .

~

20/20 or better acuity I

20/60 or worse acuity

Elemen- High College

Elemen- High College

None

tary

or None school tary

or school

more more

Standard error

7

8.03 1.78 1.12 1.70

4.70 3.85 3.5s

6.38 4.00 3.90

111.74 6.47 4.03

25.94 3.51 1.73 4.42

26.96 3.58 2.02 4.50

6.79 6.36 12.28

34.38 4.45 1.78 2.48

35.36

50.00

11.75

4.81 1.87 2.81

8.69 5.13 14.86

2.391 1.16 ] 1.10

19.36

34.41

4.57

2.54 1.19 1.10

4.59 3.32 6.78

5.o5 I 3.46 I 4.I5

8.87

12.69

17.99

25.27

9.96

14.13

14.63

6.19 3.79 4.10

5.67 9.99 18.59

tt

6.10 3.93 6.75

—

6.00 3.92 5.BI

‘11.43 9.37 33.85

3.19

29.37

34.33

37.60

7.45

9.38

21.74

12.74

62.44

10.17

5.73

25.30

8.81

8.66

18.19

0.32 0.37 0.41

2.04 0.64 1.55

0.38 - 1.67

9.21 4.18

0.84 0.60 1.91

0.90 0.79 2.04

1.19 1.06

1.50 0.85 0.79

1.69 0.85 0.82

2.30 1.92

0.66 0.39 0.20

0.78 0.45

1.40 1.07

2.72! 0.95

0.30

1.87

0.51

2,80 1.02

4.36 1.53

t

2.05 1.18

2.62 1.17

2.32. 6.51

+

2.56 1.71

3.39 2.46

4.67 5.42

0.50

3.58

0.40

0.s4

4.46

4.28

7.56

lTotals include racas other than white and Negro.

50
Table9. Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

education of head of household, age, race, and sex, with standard errors: United States, 1971 -1972–Con.

Age, r~ce,’ and sex

20/20 or better acuity 20/50 or worse acuity

Elemen- High College Elemen- High College

None

tary

or None

school tary school or

more more

Males

4-74years . . . . ..m. m..... . . .

Allreces,4-5years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . .. . . . . . . . . . .

Allraces,6-ll years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,12-17years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,18-44years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,45-54years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,55-64years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,65-74years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Percent

+H+F 36.2 6.1

0.6

2.6 1.3

1.1 1,0

19.1 40.0 40.8 -

11.5 24.8

77.7 73.5 79,5 47.9

79.5 75.0 80.2 53.7

72.7 63.8 66.1 -

83.5 87.1 88.7 -

83.9 88.0 90.8 -

0.8

1.8

1.1

3.3

.-

29.8

8.0

3.4

21.3

100.0

1.9

1.6

3.4

3.4

3.1

3.0

3.5

100.0

74.8

3.9

1.6

1.8

1.9

5.2

1.7 0.5

0.5

0.6

*

79.8

56.7

17.8

1.8

1.9

8.6

1.7

0.8

1.5

63.0

26.0 m 8.8

8.1

11.5

1.6

1.3

2.2 2.7

20.5

78.1m 11.8

7.1

14.6

2.6

2.2

11.6

2.7

10.4

20.3 27.6

I

32.7 II 38.9 23.3

15.5 28.3 16.0 60.0

12.4

33.8

12.1

30.5

11.4

22.4

lTotais include races other than white and Negro.

51
Table9. Percent of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

education of head of household, age, race, andsex, with standard errors: United States, 1971-1972-Con.

Age, race,’ and sex

Males Standard error

4-74 years . . . . , .

All races, 4-5 years . . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces,6-11 years . . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All racesr12-17 years . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 18-44 years . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

Allraces, 45-54 years . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 55-64 years . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

All races, 65-74 years . .

White . . . . . . . . . . . .

Negro . . . . . . . . . . . .

lTotals include races mher

1.12 2.15

6.02 5.30

9.83 0.89 0.52 0.60

0.65 1.04 1.10

. . . . . . . . . . . 4.30 2.08

. . . . . . . . . . . 6.46

9.30

6.98

4.66

.—

6.14

10.54

4.79

6.92 5.62

10.39

3.66 5.77

0.90 - 1.12

8.14

29.39 37.47 0.80 0.83 1.83

28.03

50.00

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . .

3.98 5.90

7.19. 20.94

1.71 2.09

40.68 1.03

1.69

1.18

1.80

. . . . . . . . . . . 1.95

. . . . . . . . . . .

. . . . . . . . . . . -1 2.00 1.11

1.83 1.52

5.23 34.23

1.43 1.93

50.00

22.17

2.54 0.81

1.50 3.14

1.25 0.77 0.46

5.56

4.12

4.60

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . .

41.45

39.73

16.97

17.09

12.40

8.17

12.86

17.70

5.70

7.37

6.69

——

8.14

9.56

7.16

——

6.77

‘14.76

4.44

——

4.69

5.31

1.49 1.64

4.75 16.01

3.32 4.02

1.36

2.02

0.87

0.80

0.50

0.62

. . . . . . . . . . .

. . . . . . . . . . .

. . . . . . . . . . . 26.271 4.97 0.96

t

3.94 3.70

15.82 36.81

4.72 8.79

5.00 8.09

18.14 46.02

2.99 4.24

3.19 5.62

13.46 28.23

21.78 4.96

62.44 6.92

1.06

1.30

. . . . . . . . . . .

. . . . . . . . . . .

t

10.45 4.26

7.43 4.29

39.33 4.00

. . . . . . . . . . , 1.70 3,01

1.64

3.13

. . . . . . . . . . . 2.94

. . . . . . . . . . ,

+

13.16 1.94

10.79 2.75

23.58 7.21

. . . . . . . . . . . 2.15 5.75

2.99

9.44

6.52

22.40

. . . . . . . . . . .

. . . . . . . . . . .

than white and Negro.

52
Table9. P¢ of the population age 4-74 years reaching specified acuity levels for usual distance vision in the better eye, by

educetionof head of household, age, race, andsex, with standard errors: United States, 1971 -1972 —Con.

Age, race,l and sex

Females

4-74years . . . . . . . . . . . . . . . . .

Allraces,4-5years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,6-ll years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces, 12-17years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces, 18-44years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,45-54years ,.. . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,55-64years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,6S74years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

20/20 or better acuity 1 20/50 or worse acu ity

v

Eiemen- High

College

EIemen- High

College

None

tary

or None

school tary

or

school

more more

Percent

36.9 60.7 71.6 77.7 10.1 5.6 3.2 2.1

19.0 32.2 19.8 - 5.4 0.3 5.3

18.4 35.9 22.3 - 6.2

21.5 7.1 5.3 - 25.2 2.0

74.5 63.3 70.9 72.7 13.6 1.6 3.0 4.3

100.0 69.8 75.1 76.2 - 1.2 3.2 4.6

47.3 45.6 28.0 53.2 2.4 1.6

45.4 76.3 79.1 84.6 - 2.9 3.9 2.1

42.1 79.4 79.9 84.2 - 2.3 4.0 2.2

100.0 66.2 71.9 92.4 - 4.7 2.7

40.7 79.3 83.3 89.4 27.7 2.9 2.1 0.6

46.2 79.1 83.8 89.5 36.5 2.8 1.7 0.4

100.0 79.6 79.9 87.3 - 3.2 4.4 3.2

62.0 67.4 78.9 4.4 5.3 3.3 1.5

59.9 67.3 79.1 4.4 5.5 3.2 1.2

71.5 69.1 91.0 - 3.9 3.9 5.7

75.1 48.0 57.9 60.3 - 6.8 2.4 2.4

41.4 45.1 58.5 59.0 - 4.5 2.1 3.7

91.3 44.9 22.5 39.4 8.7 10.2 16.9

25.1 25.0 30.5 39.9 31.1 17.3 13.6 9.4

25.6 27.7 36.6 53.2 17.3 14.7 10.6

37.1 15.6 41.2 5.6 11.0 29.5 16.4

lTotals include races other than white and Ne9ro.

53
Table9. Percent of the population age 474 years reaching specified acuity levels for usual distance vision in the batter eye, by

education of head of household, age, race, and sex, with standard errors: United States. 1971-1972—Con.

Age, race,’ and sex

Females

4-74 years . . . . . . . . . . . . . . . . .

Allracesr4-5 years . . , . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,6-ll years . . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces, 12-17years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces, 18-44years . . . . . . . . . . . . .

white . . . . . . . . , . . . . . . .- , - . , .

Negro . . . . . . . . . . . . . . . . . . . . . .

Allraces,45-54years . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

Allraces,55-64years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . , . . . . . . . . . . , . . . . , . . . . .

AllracesJ65-74years . . . . . . . . . . . . .

White . . . . . . . . . . . . . . . . . . . . . . .

Negro . . . . . . . . . . . . . . . . . . . . . . .

20/20 or better acuity I

20/50 or worse acuity

College College

ElemenNoneHigh

None

Elemen- High

tary

or

school tary

or

more

school

more

16.98

34.58

31.62

36.00

37.05

50.00

19.40

27.13

50.00

29.64

47.57

30.42

13.46

28.71

Standard error

2.56 I 1.60

=

T

5.20 6.38

—

6.93 7.18

19.98 2.82

7.04 2.72

—

6.62 2.96

9.18 8.44

6.22 2.55

7.13 2.79

15.30 7.54

3.10 1.76

+

3.08 1.72

4.62 4.04

5.99 4.72

7.47 5.31

4.88 9.56

8.65 5.51

+

9.23 5.44

13.49 10.68

3.64 3.33

—

4.15 4.78

5.25 13,42

2.45 4.94 0.81 0.34 0.58

5.88 - 4.02 0.20 3.08

7.07 - 3.55

4.74 - 15.52 1.55

5.24 16.40 0.97 0.82 2.90

5.44 - 0.80 0.99 3.12

13.27 37.60 2.01 1.08

5.47 - 1.61 0.96 1.80

5.85 - 1.66 1.02 1.91

5.45 - 3.31 1.88

1.33 122.12 I 0.98 ] 0.47 ] 0.28

1.44 28.69 1.09 0.50 0.25

4.24 - 1.88 1.65 3.22

8.52 30,93 2.70 1.50 1.25

9.05 30.93 3.28 1.60 1.28

18.09 - 2.82 2.99 8.09

9.71 - 1.43 1.59 2.48

8.04 - 3.18 1.52 2.39

36.05 30.42 2.18 11.73

5.81 9,58 3.68 3.15 4.38

7.13 9.76 4.62 3.82 4.07

10.19 16.43 6.68 10.15

lTotals include races other than white and Ne9ro.

54
Table 10. Percent of population age 18-74 years reaching specified acuity levels for usuaI distance vision in the better eye, by education

ofperson, age, andsex, with standard errors: United States, 1971-1972

Age and sex

Both sexes

18-74 years . . . . . . . . . . . . . . . . . . .

18-44 years . . . . . . . . . . . . . . . . . . . .

45-54 years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Males

18-74years . . . . . . . . . . . . . . . . . . .

18-44years . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Females

18-74years . . . . . . . . . . . . . . . . . . .

18-44years . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Education of persons

With20/200r better vision IMth 20/50 or worse vision

Elemen- High

College

Elemen- High

College

None or None

school

or

tary tary

more

school

more

Percent of persons

25.4

53.5

10.1

27.0

17.7

36.6

73.5

18.0

41.7

18.7

9.3

15.9

8.2

16.2

51.0

72.4

61.0

39.7

28.8

51.4

73.3

62.1

34.9

27.4

50.7

71.4

59.7

44.0

29.9

77.2

85.9

73.1

64.4

33.1

80.1

86.5

80.0

72.0

34.6

72.2

85.4

68.4

58.8

32.0

81.7

90.4

78.7

61.5

40.0

83.4

91.5

80.7

56.4

41.7

79.5

88.9

75.8

67.9

39.0

21.7

1.9

26.0

31.6

29.4

27.4

42.9

30.4

35.9

13.4

5.6

4.4

33.1

20.4

9.2

2.8

8.8

9.7

16.5

7.9

2.0

7.3

10.6

14.0

10.4

3.7

10.7

9.0

18.6

2.6

1.9

2.0

1.9

12.3

2.4

1.7

1.5

2.2

11.8

2.8

2.1

2.4

1.7

12.6

1.1

0.4

0.2

1.5

8.8

1.1

0.4

2.7

9.8

1.1

0.3

0.4

8.2

55
Table 10. Percent of popu Iation age 18-74 years reaching specified acuity Iavels for usual distance vision in the better eye, by education

ofperaon, age, andsex, with standard errors: United States, 1971-1972-Con.

Age and sex

Both sexes

18-74 years . . . . . . . . . . . . . . . . . . .

18-44 years . . . . . . . . . . . . . . . . . . .

45-54 years . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Males

18-74years . . . . . . . . . . . . . . . . .

18-44years . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Females

18-74years . . . . . . . . . . . . . . . .

18-44years . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Education of persons

With 20/20 or better vision I

With 20/50 or worse visicm

Elemen- High

College

None None

Elemen- High

tary

or

school tary

more

school

Standard error

4.97

17.85

4.08

10.54

7.72

10.95

24.05

13.99

21.06

11.42

3.83

10.11

13.31

7.53

2.24

4.74

6.23

5.72

2.91

3.91

7.29

7.29

6.25

3.87

2.32

3.88

6.92

7.98

3.82

1.06

1.04

2.62

3.88

2.78

1.26

1.44

3.14

4.92

3.48

1.58

1.51

3.75

4.66

3.85

2.03

1.17

4.62

6.41

4.36

2.59

2.07

3.90

8.96

4.00

2.85

1.15

8.36

5.96

6.36

6.16

1.97

20.52

16.30

6.31

9.47

20.68

18.46

9.74

3.92

7.02

30.93

25.12

6.73

0.65

1.15

3.28

2.63

2.18

1.30

1.55

4.18

4,06

1.83

0.95

1.58

4.54

2.22

2.97

0.39

0.33

0.82

0.89

2.03

0.51

0.58

0.98

1.71

2.43

0.42

0.49

1.16

1.14

3.38

College

or

more

.—

0.48

0.18

0.14

1.62

4.36

0.72

0.45

2.93

5.88

0.45

0.19

0.35

4.14

56
Table Il. Percent distribution of adults age 18-74 years reaching specified acuity Ievels for usual distance vision in the better eye,

according toageand sex: United States, 1960-1962 and 1971-1972

Age and sex

Both sexes

18-24 years . . . . . . . . . . . . . . . . . . . .

25-34 years . . . . . . . . . . . . . . . . . . . .

3544years . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Males

18-24years . . . . . . . . . . . . . . . . . . . .

25-34years . . . . . . . . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

Females

18-24years . . . . . . . . . . . . . . . . . . . .

25-34years . . . . . . . . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . .

United States, 1860-1962 !

United States, 1971-1972

i I I i I

1

20120 20/25- 2o150-20/200 20/20

20125- 20150-

20/200

or

20/40 20/1 00 ‘r

or

better better

20/40 20/1 00 ‘r

worse worse

81.2

85.5

83.4

61.8

39.8

26.1

82.6

88.9

85.1

68.2

40.0

31.2

80.0

82.4

81.6

55.6

39.5

21.8

17.7

13.0

15.0

33.4

51.4

55.7

16.2

10.2

13.6

28.1

52.3

51.3

19.0

15.6

16.6

38.3

50.5

59.3

0.9

1.2

1.3

4.0

7.4

15.2

1.2

0.8

0.9

3.2

6.4

15.4

0.6

1.5

1.6

4.9

8.5

15.2

Percent distribution

0.2

0.3

0.3

0.8

1.4

3.0

0.1

0.4

0.5

1.3

2.1

0.4

0.5

0.2

1.2

1.5

3.7

87.6

84.2

85.4

71.2

56.0

32.0

8B.5

83.8

87.9

75.1

56.9

31.5

86.5

84.7

82.8

67.5

55.3

32.3

10.1

14.3

13.9

25.6

39.3

53.9

9.B

14.8

11.6

21.8

37.9

55.0

10.6

13.8

16.1

28.1

40.6

53.2

1.5

1.5

0.7

3.0

4.1

12.8

0.6

1.4

0.5

, 3.0

5.1

12.5

2.3

1.5

1.0

3.0

3.3

12.9

0.8

0.0

0.2

0.6

1.3

1.1

0.1

0.1

1.0

0.6

0.1

0.4

0.8

1.6

57
Table 12. Percent distributicm of youths age 12-17 years reaching specifieal acuity Ievelsfar usual distance vision in the better eye, according toage and sex,

with standard errors for totals: United States, 1966 -1970 and 1971-1972

Acuity level “with usual correction’’–Snellen ratio

United States, 1966.1970 United States, 1971-1972

Age and sex

Both sexes Percent distribution of youths

12-17 vears 80.3 12,5 2.7 0.9 0.6 82,8

3.9

3.5

2.3

2.8

2.4

1.3

2,6

3.0

—,

3.6

4.3

3.3

2.6

2.0

2.2

2.6

11.7 2,8 1.9 0,5 0.3

12 years . . . . . . . . . . . . . . .

13 years . . . . . . . . . . . . . .

14years . . . . . . . . . . . . . .

15years . . . . . . . . . . . . . .

16years .

17years . . .

74.0

76.8

80.9

80.4

84.3

86.6

82.3

16.7

13.7

11.7

13.0

10.5

8.7

11.4

1.0

0.9

0.8

0.7

0.6

1.0

0.6

0.8

0.8

1.0

0.5

0.2

0.2

0.5

0.3

0.5

1.2

0.3

0.3

0.2

0.8

75,5

80.6

83.0

84.2

87.3

86.6

86.6

80.1

85.3

86.5

85.3

92.4

91.0

79.0

15.5

11.2

10.8

11.7

10.1

10,9

9.4

15.3

8.4

9.4

9.2

4.8

8.1

14.0

5,5

4.4

2.6

1.1

0.9

1.9

1.7

3.0

1,8

2.4

2.9

0.7

0,5

1.5

0.3

0.6

1.1

1.0

0.1

0.5

0.2

1.4

0.1

0.1

0.3

Boys

12-17years

12years

13years, .,, , . . . . . . . . .

14years . . . . . . . . . . . . . ,.

15years . .

16years ,.

17years

77.7

60.3

81.4

81.7

84.9

88.8

78,3

70.2

73.2

80.5

79.1

83.7

84.3

15,1

11.6

11.9

12.1

10.1

6.9

13,5

3.0

3.3

2.3

3.0

2.2

1.5

2.9

2.7

3.1

3,2

2.6

2,3

1.8

3.4

1.2

1,2

0,3

0.2

0.8

1.1

3.2

5.0

0.4

0.4

1.7

3.8

0.4

1.4

5.1

1.1

0.7

2.3

0.6

2.0

0.2

0.6

0.4

1.3

0.3

0.3

Girls

12-17years .

12years .,, , . . . . . . . . .

13years

14years, . . . . . . . . . . . .

15years, , . . . . . . . . . . .

16years ,.

17years ., . . ...,,.... ,,

18.3

15,6

11.4

13.8

10.9

10.7

4.9

3.8

2.2

2.6

2.6

1.0

4.6

5.5

3.4

2.6

1.7

2.6

0.8

0.7

1.7

1.?

1.0

1.2

1.2

1.2

0.8

0.8

0.1

0.2

69.6

76.8

79.8

83.0

82.7

81.1

15.5

13.5

12.0

14.6

14.8

14.4

8.5

3.9

4.6

2.0

0.2

4.3

6.4

3.1

3.4

0.2

0.4

0.2

1.2

0.2

1,9

1.5

0.2

Standard error

Both sexes, 12.17 years

8oys,12-17years . .

Girls,12-17vears . .
Table 13. Percent distribution of children age 6-11 years reachirsts apacifiadacuitv Ievelsfor distance vision inthebatter eye, ’’without comection’’ and

''with usual correction,' 'according toqeand wx, with Wndarderrom fortotals: Unitad States, 1963-1965 and 1971-1972

“Without correction” I

‘With usual correction”

United Stat

I I

S, 1963-1965 I

United States, 1971-1972

I t 1 I

Age and sex

20/50-

20/70

20/60-

20/100

20/200

or

worse

20/20 20/25

or 20/30 m/40

better

Both sexes Percent distribution of children

2.8 0.5

0.2

2.9

0.1

0.2

62.0 24.2 0.2

30.9

32.6

27.9

19.6

17.3

15.9

22.7

611veam . . . . . . . . . . 4.4 1.3 3.3 72.5 21.1 2.9

6.4

5.5

3.6

3.6

2.5

4.6

4.0

4.8

3.1

4.2

5.2

4.5

5.7

5.8

4.5

44.5

23.4

20.5

10.2

14.2

16.5

18.7

42.5

16.1

27.2

10.3

7.3

14.9

23.5

46.5

32.9

13.9

9.9

20.3

18.1

2.4

2.6

2.4

3.1

0.3

6.2

3.4

58.8

55.1

59.8

67.8

67.2

64.1

64.5

0.5

1.0

1.1

1.1

2.4

2.2

1.3

0.3

1.6

2.4

3.4

4.9

7.4

3.0

0.3

2.2

I.5

3.1

3.6

7.2

3.5

51.5

70.2

75.3

80.1

81.4

74.3

74.9

56.5

77.2

67.3

80.3

90.9

71.6

70.1

1.6

3.8

0.5

3.7

4.0

2.9

2.5

6years . . . . . . . . . . . . . .

7yeara . . . . . . . . . . . . . .

8yeare . . . . . . . . . . . . . .

9years . . . . . . . . . . . . . .

10years . . . . . . . . . . . . .

11 years . . . . . . . . . . . . .

1.1

0.1

BOYS

6-llveara . . . . . . . . . . 0.3

0.8

3.8

0.7

6.2

1.5

0.7

3.3

2.4

3.7

0.3

1.0

6.3

4.9

0.2

2.9

2.4

2.1

0.3

12.8

2.2

4.3

2.3

2.4

4.3

0.4

64.5

57.8

60.8

69.6

70.7

65.1

59.3

27.3

29.3

26.8

19.4

16.0

16.3

25.8

4.5

6.3

3.7

2.9

2.2

4.2

4.9

2.7

2.7

5.7

4.1

5.9

5.5

5.1

0.7

1.6

1.1

0.9

1.6

1.7

1.4

6years . . . . . . . . . . . . . .

7Vears . . . . . . . . . . . . . .

8years . . . . . . . . . . . . . .

9years . . . . . . . . . . . . . .

10years . . . . . . . . . . . . .

11 yeara . . . . . . . . . . . . .

0.3

1.1

0.9

2.1

Girls —

&llvaars . . . . . . . . . . 0.0

53.0

52.3

58.6

66.1

63.5

62.8

34.7

35.8

28.9

19.8

18.6

15.7

8.4

4.7

3.6

4.4

2.9

4.9

3.4

5.9

4.8

4.8

5.7

6.2

0.2

0.4

1.2

1.2

3.2

2.7

0.3

0.9

2.9

3.7

6.1

7.7

6years . . . . . . . . . . . . . . 46.8

7years . . . . . . . . . . . . . .

8years . . . . . . . . . . . . . .

9years . . . . . . . . . . . . . .

lovers . . . . . . . . . . . . .

11 years. . . . . . . . . . . . .

4.9

0.2

61.1

83.4

79.9

72.9

76.8

.-

0.1

Stand ard error

1.34 0.87 0.40 0.26 0.15 0.28 1.72 1.50 0.59 0.75 0.30 0.16

1.65 1.08 0.48 0.45 0.22 0.40 2.63 2.33 0.73 1.14 0.20 0.31

1.46 1.21 0.51 0.29 0.20 0.46 1.64 1.% 1.02 0.79 0.59 0.02

Both sexes,6-llvears . .

60ys,6-ll yeara . . . . . . . . .

Girls,611vears . . . . . . . . .

.i

59
Table 14. Percent of adults age 18-79 years with defective binocular distance and/or near visual acuity with usual correction, by age

and sex: United States, 1960-1962

Defective I I

I

Defective

Age and sex

Both sexes

18-79 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-24 years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25-34yaars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75-79years . . . . . . . . . . . . . . . . . . . . ..’...... . . . . . . . .

Males

18-79years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-24years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25-34years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75-79years, . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Females

18-79years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

18-24years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

25-34years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

35-44years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

45-54years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

55-64years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

65-74years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

75-79years . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

distance

and

near’

. . .

0.3

0.7

0.8

1.6

4.3

10.4

21.5

. . .

0.0

0.5

0.9

1.2

3.8

9.9

18.7

. . .

0.6

1.0

0.8

2.0

4.8

10.8

24.3

Percent

. . . . . .

0.7

1.5

1.5

4.3

7.9

16.3

28.4

. . .

0.2

0.9

1.5

3.5

7.2

16.2

23.3

. . .

1.2

1.9

1.5

5.0

8.4

16.3

33,3

1.4

1.7

5.8

26.5

27.6

33.6

57.0

. . .

1.1

2.3

3.5

27.0

32.0

35.2

56.6

. . .

1.6

1.3

7.8

25.9

23.5

32.6

57.5

. . .

.—-—

1.8

2.5

6.5

29.2

31.2

39.5

63.9

. . .

-—

1.3

2.7

4.1

29.3

35.4

41.5

68.2

. . .

2.2

2.2

8.5

28.9

27.1

38.1

66.5

1 Defective distance binocular acuity < 20/50, usual; defectiva near bitIOCUlar aCUkY ~ 14/35, usual.

60
The Survey Design

The sampling plan

APPENDIX I

STATISTICAL NOTES

for the first 65 stands of

the Health- an~ Nutrition Examination Survey

(HANES) followed a stratified, multistage probability design in which a sample of the civilian

noninstitutionalized population, 1-74 years of

age, of the coterminous United States, was

selected. Excluded from the selection were

persons residing in Alaska and Hawaii and those

within the coterminous United States who were

confined to institutions or residing on reservation lands of American Indians. Successive elements dealt with in the process of sampling were

the primary sampling unit, census enumeration

district, segment (a cluster of households),

household, eligible persons, and, finally, sample

persons.

The starting points in the first stage of this

design were the 1960 decennial census lists of

addresses and the nearly 1,900 primary sampling

units (PSU’S) into which the entire United States

was divided. Each PSU is either a standard

metropolitan statistical area (SLMSA), a single

county, or two or three contiguous counties.

The PSU’S were grouped into 357 strata for use

in the Health Interview Survey and subsequently

collapsed into 40 superstrata for use in Cycles 11

and III of the Health Examination Survey and

HANES.

Fifteen of the forty superstrata contained a

single large metropolitan area of more than 2

million population. These 15 large metropolitan

areas were selected for the sample with certainty. The 25 noncertaint y strata were classified into 4 broad geographic regions of approximately equal population and cross-classified into

4 broad population density groups in each

region. Then a modified Goodman-Kish controlled selection technique was used to select 2

PSU’S from each of the 25 noncerta.inty superstrata with the probability of selection of a PSU

proportionate to its 1960 population so that

proportionate representation of specified State

groups and rate of population change classes was

maintained in the sample. In this matter a total

first stage sample of 65 PSU’S was selected.

These 65 sample PSU’S or stands are the areas

within which samples of persons would be

selected for examination over a 3-year survey

period.

In order to produce national estimates of the

nutritional status of the U.S. population at an

earlier date, a probability subsample of 35

stands of the 65 stands was selected. This

35-stand subsample also made it possible to

produce national estimates of certain other

aspects of health status in the population that

were critically needed at an earlier date and

examination components that for logistic reasons could not be continued for the remainder

of the 65 stands. Included among the 35 stands

were 10 of the 15 large certainty metropolitan

areas and 1 stand from each of the 25 noncertainty superstrata. The reduction from 15 to 10

large metropolitan areas was accomplished by

randomly selecting one stand from multiplestand standard metropolitan statisticalareas; e.g.,

selecting the southern half of the Chicago SMSA

to represent the entire SMSA. (This selection

procedure was based on operational considerations, and although unbiased, is recognized as

61
not being statistically optimal. ) It is this subsample of 35 stands upon which the findings

contained in this report are based.

Although the 1970 census data were used as

the frame for selecting the sample within PSU’S

when they became available, the calendar of

operations required that 1960 census data be

used for the 35-stand sample of HAN13S. Census

enumeration districts (ED’s) in each PSU were

divided into segments of an expected six housing

units each. In urban ED’s the segments were

clusters of six addresses from the 1960 census

listing books. For ED’s not having usable addresses, area sampling was employed and consequently some variation in the segment size

occurred. To make the sample representative of

the then-current population of the United

States, the address or list segments were supplemented by a sample of housing units which had

been constructed since 1960.

Within each PSU a systematic sample of

segments was selected. The enumeration districts

that fell into the sample were codecl into one

of two economic classes. The first class, identified as the “poverty stratum,” was composed of

“current poverty areas” that had been identified

by the Bureau of the Census in 1970 (pre-1970

census), plus other ED’s in the PSU with a mean

income of less than $3,000 in 1959 (based on

1960 census). The second economic class, the

“nonpoverty stratum,” included all ED’s not

designated as belonging to the poverty stratum.

All sample segments classified as being in the

poverty stratum were retained in the sample.

For those sample segments in nonpoverty

stratum ED’s, the selected segments were divided into eight random subgroups and one of

the subgroups was chosen to remain in the

HANES sample. This procedure permitted a

separate analysis with adequate reliability of

those classified as being below the poverty level

and those classified as being above the poverty

level.

After identification of the sample segments, a

list of all current addresses within the segment

boundaries was made, and the households were

interviewed to determine the age and sex of each

household member, as well as other demographic and socioeconomic information required

for the survey.

To select the persons in sample segments to

be examined in HANES, all household members

age 1-74 in each segment were listed on a sample

selection worksheet with each household in the

segment listed serially. The number of household members in each of the six age-sex groups

shown below was listed on the worksheet under

the appropriate age-sex group column.. The

sample selection worksheets were then put in

segment number order and a systematic random

sample of persons in each age-sex group was

selected to be examined using the following

sampling rates:

Age in years Rate

1-5 . . . . . . . . . . . . . . . . . . . . . . . . . . . 1/2

6-19 . . . . . . . . . . . . . . . . . . . . . . . . . . 1/4

20-44, mace . . . . . . . . . . . . . . . . . . . . . . 114

20-44, female . . . . . . . . . . . . . . . . . . . . , 1/2

45-64 . . . . . . . . . . . . . . . . . . . . . . . . . . 1/4

65-74 . . . . . . . . . . . . . . . . . . . . . . . . . . 1

The persons selected in the 35-stand ~sample

of HANES comprised a representative sample of

the target population and included 14,147 sample persons 1-74 years of age of whom 10,126 or

71.6 percent were examined. When adjustments

are made for differential sampling for high-risk

groups, the response rate becomes 72.8 plercent.

All data presented in this report are based on

weighted observations; that is, data recorded for

each sample person are inflated to characterize

the subuniverse from which that sample person

was drawn. The weight for each examined

person is a product of the reciprocal of the

probability of selecting the person, an adjustment for nonresponse cases (i.e., perso:ns not

examined), and a poststratified ratio adjustment

which increases precision by bringing survey

results into closer alinement with known U.S.

population figures.

A more detailed description of the survey

design and selection technique can be found in

the Plan and Operation of a Health and Nutritio n Examination Survey, United States,

1971-1973, Vital and Health Statistics, Series 1,

No. 10a.6

Nonresponse

In any health examination survey, after the

sample is identified and the sample perscms are

62
requested to participate in the examination, the

survey meets one of its more severe problems.

Usually a sizable number of sample persons wilI

not participate in the examination. Whether or

not an individual participates is determined by

many factors, some of which are uncontrollable

and, therefore, may be reasonably treated as an

outcome of a random event with a particular

probabilityy of occurrence. If these probabilities

of participation were known and greater than

zero for all persons, then the examined persons

would constitute a probability sample from

which unbiased estimates of the target population could be derived. In this situation, the

effect of nonparticipation would only be to

reduce the sample size, thereby increasing the

sampling errors of examination findings. However, m practice, a potential for bias due to

nonresponse exists since the exact probabilities

are never known. A further potential for bias

exists if a sizable proportion of sample persons

have a zero probability of participation, that is,

they would never agree to participate in an

examination survey of the same procedures and

inducements, and if these persons differ from

other sample persons with respect to characteristics under examination. It is for these reasons

that intensive efforts are made in HANES to

develop and implement procedures and inducements that would reduce the number of nonrespondents and thereby reduce the potential of

bias due to nonresponse. These procedures and

inducements are discussed in the “Plan and

Operation of the Health and Nutrition Examination Survey,“ Series 1, No. 10a.6

Despite these intensive efforts, 27.2 percent

of the sample persons from the first 35 stands

were not examined. Consequently, the potential

for a sizable bias does exist in the estimates in

this publication. From what is known about the

nonrespondents and the nature of nonresponse,

it is believed that the likelihood of sizable bias is

small. For instance, only a small proportion of

persons gave reasons for nonparticipation which

would lead to the belief that they would never

agree to participate in examination surveys and

that they may differ from examined persons

with respect to the characteristic under examination. Only 15 percent of the nonrespondents

gave as their reasons for nonparticipation

“personal illness,“ “physically unable,” “pregnant,” “ antidoctor,” or “fear of finding something wrong.” Typical among the reasons given

by the other nonrespondents were the following: “unable because of work, school, or household duties”; “suspicious” or “skeptical of the

program”; “just not interested in participating”;

and “private medical care sufficient” or “just

visited doctor.”

An analysis of medical history data obtained

for most nonexaminees as well as examinees also

supports the belief that the likelihood of sizable

bias due to nonresponse is small. No large

differences were found between the examined

group and nonexamined group for the statistics

compared. For example, 11 percent of persons

examined reported having an illness or condition

that interfered with their eating as compared

to 9 percent of persons who were not examined

but who had completed a mediczd history. The

percent of persons examined who reported ever

being told by a doctor that they had arthritis

was 20 percent; the percent for high blood

pressure was 18 percent, and for diabetes was 4

percent. The corresponding percents for nonexamined persons were 17 percent for arthritis,

21 percent for high blood pressure, and 4

percent for diabetes.

As mentioned eadier, the data in this report

are based on weighted observations, and one of

the components of the weight assigned to an

examined person was an adjustment for nonresponse. Since the probabilities of participation

are not known for sample persons in HANES, a

procedure was adopted which multiplies the

reciprocal of the probability of selection of

sample persons by a factor that brings estimates

based only on examined persons up to a level

that would have been achieved if all sample

persons had been examined. This nonresponse

adjustment factor is the ratio of the sum of

sampling weights for all sample persons within a

relatively homogeneous class defined by age,

sex, and poverty status, to the sum of sampling

weights for all responding sample persons within

the same homogeneous class. To the degree that

homogeneous groups can be defined which are

also homogeneous with respect to the characteristics under study, the procedure can be effective in reducing the potential bias from nonresponse.

For the 35-stand sample of HANES, persons

were grouped into 20 age-sex-poverty status

groups within each stand, yielding 700 separate

63
cells with an average membership of about 20

sample persons each. These adjustment fdctors

are distributed among examined persons as

shown in table 1.

Missing Data

Examination surveys are subject to the loss of

information not only through the failure to

examine all sample persons, but also from the

failure to obtain and record all items of informaTable 1. Percent distribution of nonresponse adjustment

factors: Health and Nutrition Examination Survey,

Stands 1-35, 1971-1972

Size of factor Percent

distribution

Total . . . . . . . . . . . . . . . .

1.00-1 .24 . . . . . . . . . . . . . . . .

1.25-1 .49 . . . . . . . . . . . . . . . .

1.50-1 .74 . . . . . . . . . . . . . . . .

1.75-1 .99 . . . . . . . . . . . . . . . .

2.002.49 . . . . . . . . . . . . . . . .

2.50-2.99 . . . . . . . . . . . . . . . .

3.00-3.03 . . . . . . . . . . . . . . . .

100.0

38.4

31.6

12.9

8.4

6.1

1.2

1.4

tion for examined persons. The extent of missing data for the visual acuity testing ranged from

3 to 5 percent for persons age 6-74 years but

among 4- and 5-year-olds more than one-fifth

(22 percent) did not have visual acuity readings.

The extent of missing data for those visual

acuity tests is shown in table II.

Estimates were made for the missin~ visual

acuity scores as follows. For each examined

person with some (but incomplete) record of

visual acuity, a visually examined respondent of

the same age, sex, race, and income group with

relevant findings similar to those available for

the incompletely examined person was selected

at random and the remainder of those test

results were assigned to the individual with those

missing values.

In doing this imputation, persons whose

examination showed an enucleated globe were

classed as blind in that eye; selection of :missing

data for persons with cataracts was made from

among those with cataracts whose visual acuity

had been determined. If visual acuity for one

eye was available and other examination findings

indicated no problems with the other eye, the

vision data for that eye were imputed to the

other eye. For those examined persons whose

visual acuity had not been recorded, a visually

examined respondent of the same age, sex, race,

Table 11. Number of examinees and extent of visual acuity tests imputed, by age: HANES 1, 1971-1972

Examinees and acuity tests imputed

All examinees . . . . . . . . .

Number not tested

(Percent).....::::::::::

Uncorrected:

Right eye . . . . . . . . . . . . . .

Lefteye . . . . . . . . . . . . . . .

Both eyes . . . . . . . . . . . . . .

Corrected:

Right eye . . . . . . . . . . . . . .

Left eye . . . . . . . . . . . . . . .

Both eyes . . . . . . . . . . . . . .

I Includes eight 75-year-olds.

Age in years

=1 I “2-17 I ‘8-24 I 2’-34 I 3544 I 45-54 I 5’44 I ‘Z

Number of examinees

1

9,263 626

504 136

(5.4) (21 .7)

14 3

11

354 133

15

23 -

87 - I

1,087 1,045

=

47 47

(4.4) (4.5)

1 1

1 2

45 40

2

2

—

1,015

31

(3.1 )

2

1

24

4

1,259

49

(3.9)

1

41

1

6

1,170

(5:

2

2

32

3

21

793

(35

2

1

12

3

3

6

630

(35

1

1

5

2

3

12

1,658

(58

2

2

22

10

11

36

64
and income group was selected at random and

his test results were assigned to the individual

with missing acuity data.

This imputation procedure was used because

it would tend to distort the national estimates

less (than the alternative of deleting all those

persons with missing visual acuity data) if one

assumed that the distribution of visual acuity

values among those persons with missing data by

age, sex, race, and other variables would be

similar to values for those tested.

Small Numbers

In some tables, magnitudes are shown for cells

for which the sampIe size is so small that the

sampling error may be severaI times as great as

the statistic itself. Obviously in such instances

the numbers, if shown, have been included to

convey an impression of the overall story of the

table.

Sampling and Measurement Error

In the present report, reference has been

made to efforts to minimize bias and variability

of measurement techniques. The potential of

residual bias due to the high nonresponse rate

has also been discussed.

The probability design of the survey makes

possible the calculation of sampIing errors.

Traditionally the role of the sampling error has

been the determination of how imprecise the

survey results may be because they come from a

sample rather than from the measurement of all

elements in the universe.

The estimation of sampling errors for a study

of the type of the Health and Nutrition Examination Survey is difficult for at least three

reasons: (1) measurement error and “pure”

sampling error are confounded in the data—it is

not easy to find a procedure that will either

completely include both or treat one or the

other separately; (2) the survey design and

estimation procedures are complex and, according y, require computationally involved techniques for the calculation of variances; and (.3)

hundreds of statistics are presented in the tables

in this report, many for subclasses of the

population for which there were small numbers

of sample cases. Estimates of sampling error are

obtained from the sample data and are themselves subject to sampling error when the number of cases in a ceil is smrdl or, even occasionally, when the number of cases is substantial.

Estimates of the standard errors for selected

statistics used in this report are presented in the

detailed tables. These estimates have been prepared by a replication technique that yields

overall variability through observation of variability among random subsamples of the total

sample. Again, readers are reminded that these

estimated sampling errors do not reflect any

residual bias that might still be present after the

attempted correction for nonresponse. The

standard error is primarily a measure of sampIing

variability; that is, the variations that might

occur by chance because ordy a sample of the

population has been surveyed. As calculated for

this report, the standard error also reflects part

of the variation that arises in the measurement

process. It does not include estimates of any

biases that might exist in the data. The chances

are about 68 out of 100 that an estimate from

the sample would differ from a complete census

by less than the standard error. The chances are

about 95 out of 100 that the difference would

be less than twice the standard error and about

99 out of 100 that it wouId be less than 2%

times as large.

000

65
APPIENDIX II

DEMOGRAPHIC AND SOCIOECONOMIC TERMS

Age. –The age recorded for each examinele

was the age at last birthday at the time of

examination. The age criterion for inclusion in

the sample used in this survey was defined as

age at time of census interview. In this sample

there were a few examinees who were 74 years

of age at the time of interview but 75 years of

age at examination. In the adjustment and

weighting procedures used to produce national

estimates, these persons were included in the

74-year-old group.

Race. –Race was recorded as “white,”

“Negro,” or “other.” “Other” includes Japanese, Chinese, American Indian, IKorean, Eskimo, and all races other than white and Negro.

Mexicans were included with white unless definitely known to be American Indian or of other

nonwhite race. Negroes and persons of mixed

Negro and other parentage were recorded as

Negro. When a person of mixed racial background was uncertain about his race, the race of

his father was recorded.

Geographic rep”on. –The 48 contiguous State:;

and the District of Columbia (not Alaska and

Hawaii) were stratified into 4 broad geographic

regions of about equal population size. With a

few exceptions the compositions of the regiom

were as follows:

Region

Northeast . . . .

Midwest . . . . .

South . . . . . . .

States included

Maine, New Hampshire, Vermont, Massachusetts, Connecticut, Rhode Island, New

York, New Jersey, Pennsylvania

Ohio, Michigan, Indiana, Illinois, Wisconsin,

Minnesota, Iowa, Missouri

Delaware, Maryland, Virginia, West Virginia,

Kentucky, Arkansas, Tennessee, North

Carolina, South Carolina, Georgia, Florida,

Alabama, Mississippi, Louisiana; District of

Columbia

West . . . . . . . . Washington, Oregon, Idaho, Montana,

Wyoming, Colorado, Utah, Nevada, California, Arizona, New Mexico, Texas, Oklahoma, Kansas, Nebraska, South Dakota,

North Dakota

In a few instances the actual boundaries of

the regions do not follow State lines. Some

strata in the Midwest and South include PSU’S

actually located in the West. Similarly, some

strata in the West contain PSU’S located in the

Midwest and South.

Urban-rural. –The classification of urban-rural

areas is that used in the 1960 census. According

to the 1960 definition, those areas considered

urban are: (1) places of 2,500 inhabitants or

more incorporated as cities, boroughs, villages,

and towns (except towns in New England, New

York, and Wisconsin); (2) the densely settled

urban fringe, whether incorporated or unincorporated, of urbanized areas; (3) towns in New

England and townships in New Jersey and

Pennsylvania that contain no incorporated municipalities as subdivisions and have either 2,500

inhabitants or more, or a population of 2,500 to

25,000 and a density of 1,500 persons per

square mile; (4) counties in States other than the

New England States, New Jersey, and Pennsylvania that have no incorporated municipalities

within their boundaries and have a density of

1,500 persons or more per square mile; and (5)

unincorporated places of 2,500 inhabitants or

more which are not included in an37 urban

fringe. The remaining population is classified as

rural.

66
By means of the first digit of the identification code on the household questionnaire, the

urban and rural population is divided into the

following categories according to population:

(1) urban, 3,000,000 or more; (2) urban,

1,000,000-2,999,999; (3) urban, 250,000-

999,999; (4) urban, under 250,000; (5) urban

not in urbanized area, 25,000 or more; (6) urban

not in urbanized areas, 10,000-24,999; (7) urban

not in urbanized area, 2,500-9,999; and (8)

rural.

Family income. –The income recorded is the

total income received during the 12 months

prior to the interview by the head of the

household and all other household members

related to the head. This income is the gross cash

income (excluding pay in kind) except in the

case of a family with its own farm or business.

In that instance net income is recorded. Also

included is the income

Armed Forces living at

of a

home

member of the

with his family

o

(even though he is not considered a household

member). If he is not living at home, allotments

and other money received by the family from

him are included in the family income figure.

Education. –The only grades counted are

those that have been attended in a “regular”

school where persons are given formal education–either graded public or private schools, day

or night, full-time or part-time attendance. A

regular school is one that advances a person

toward an elementary certificate or high school

diploma, or a college, university, or professional

school degree. Education received in vocational,

trade, or business schools outside the regular

school system is not counted in determining the

highest grade of schooI completed. If a person

attended school in a foreign country, at an

ungraded school, under a tutor, or under other

special circumstances, the nearest equivalent of

his highest grade attended is assigned.

00

*U.S. GOVERNMENT PRINTING OFFICE: 1977-241.1805

67
T

Sen”es 1.

Sen-es 2.

Series 3,

Sert”es 4.

VITAL AND HEALTH STATISTICS PUBLICATIONS SERIES

Formerly public Health Service publication No. 1000

Programs and Collection I+ocedures. –Reports which describe the general programs of the National

Center for Health Statistics and its offices and divisions, data collection methods used, definitions, and

other material necessary for understanding the data.

Data Evaluation and Methods Research. –Studies of new statistical methodology including experimental

tests of new survey methods, studies of vital statistics collection methods, new analytical techniques,

objective evaluations of reliability of collected data, contributions to statistical theory.

Analytical Studies. –Reports presenting analytical or interpretive studies based on vital and health

statistics, carrying the analysis further than the expository types of reports in tbe other series.

Documents and Co remittee Reports. –Final reports of major committees concerned with vital and

health statistics, and documents such as recoin-mended model vital registration laws and revised birth

and death certificates.

Series 10. Data from the Health Interview Survey. –Statistics on illness; accidental injuries; disability; use of

hospital, medical, dental, and other services; and other health-related topics, based on data collected in

a continuing national household interview survey.

Series 11. Data j+om the Health Examination Survey. –Data from direct examination, testing, and measurement

of national samples of the civilian, noninstitutionalized population provide the basis for two types of

reports: (1) estimates of the medically defined prevalence of specific diseases in the United States and

the distributions of the population with respect to physical, physiological, and psychological characteristics; and (2) analysis of relationships among the various measurements without reference to an

explicit fiiite universe of persons.

Series 12. Data from the Institutionalized Population Surveys. –Discontinued effective 1975. Future reports from

these surveys will be in Series 13.

Serz”es 13. Data on Health Resources Utilization. –Statistics on the utilization of health manpower and facilities

providing long-term care, ambulatory care, hospital care, and family planning services.

!%n”es 14. Data on Health Resources: Manpower and Facilities. -Statistics on the numbers, geographic distribution, and characteristics of health resources including physicians, dentists, nurses, other health occupations, hospitals, nursing homes, and outpatient facilities.

Series 20. Data on Mortality .-Various statistics on mortality other than as included in regular annual or monthly

reports. Special anal yses by cause of death, age, and other demographic variables; geographic and time

series analyses; and statistics on characteristics of deaths not available from the vital records, based on

sample surveys of those records.

Sm”es 21. Data on Natality, Marriage, and Divorce. –Various statistics on natality, marriage, and divorce other

than as included in regular annual or monthly reports. Special analyses by demographic variables;

geographic and time series analyses; studies of fertility; and statistics on characteristics of births not

available from the vital records, based on sample surveys of those records.

Sm”es 22, Dab from the National Mortality and Natality Surveys. –Discontinued effective 1975. Future reports

from these sample surveys based on vital records will be included in Series 20 and 21, respectively.

Serz”es23. Data from the National Survey of Family Growth. –Statistics on fertility, family formation and dk.solution, family planning, and related maternal and infant health topics derived from a biennial survey of

a nationwide probability sample of ever-married women 15-44 years of age.

For a list of titles of reports published in these series, write to: Scientific and Technical Information Branch

National Center for Health Statistics

Public Health Service, HRA

Rockville, Md. 20857