Van B. Nakagawara

Ron W. Montgomery

Kathryn J. Wood

Civil Aerospace Medical Institute

Federal Aviation Administration

Oklahoma City, OK 73125

July 2009

Final Report

Evaluation of Next-Generation 

Vision Testers for Aeromedical 

Certification of Aviation Personnel

DOT/FAA/AM-09/13

Office of Aerospace Medicine

Washington, DC 20591

OK-09-0434-JAH

Federal Aviation

Administration
NOTICE

This document is disseminated under the sponsorship 

of the U.S. Department of Transportation in the interest 

of information exchange. The United States Government 

assumes no liability for the contents thereof.

___________

This publication and all Office of Aerospace Medicine 

technical reports are available in full-text from the Civil 

Aerospace Medical Institute’s publications Web site: 

www.faa.gov/library/reports/medical/oamtechreports
iii

Technical Report Documentation Page 

1. Report No. 2. Government Accession No. 3. Recipient's Catalog No. 

DOT/FAA/AM-09/13 

4. Title and Subtitle 5. Report Date 

July 2009

6. Performing Organization Code 

 

Evaluation of Next-Generation Vision Testers 

for Aeromedical Certification of Aviation Personnel

 

7. Author(s) 8. Performing Organization Report No. 

Nakagawara VB, Montgomery RW, Wood KJ 

9. Performing Organization Name and Address 10. Work Unit No. (TRAIS) 

 

 

11. Contract or Grant No. 

FAA Civil Aerospace Medical Institute 

P.O. Box 25082 

Oklahoma City, OK 73125 

07-CRDA-0231, 07-CRDA-0232 

12. Sponsoring Agency name and Address 13. Type of Report and Period Covered 

 

 

 14. Sponsoring Agency Code 

Office of Aerospace Medicine 

Federal Aviation Administration 

800 Independence Ave, S.W. 

Washington, D.C. 20591 

 

15. Supplemental Notes 

 

 16. Abstract 

Introduction. The Federal Aviation Administration (FAA) allows the use of a variety of vision screening devices to 

evaluate a pilot applicant’s vision performance for medical certification purposes. This study compares human 

subject test scores obtained using two new vision testing instruments (Optec 5000 and Titmus i400) with those 

from previously approved counterparts (Optec 2000 and Titmus 2A), which have been discontinued by their 

manufacturers. Method. Testing included near, intermediate, and distant visual acuity, when appropriate, as well 

as heterophoria and color perception. Aside from color vision deficiencies, visual performance for all subjects was 

within the minimum Federal Aviation Regulations (FAR) vision requirements for Class II airmen. The test subject 

population included 36 individuals who ranged in age from 18 to 66 (34.4 ± 14.2). Six subjects were 50 years of 

age or over, requiring intermediate vision testing and 12 were color deficient. Analysis was designed to detect 

statistically significant differences between the test scores obtained with the new instruments vs. the older models. 

Results. The results of this study indicate that both new instruments provided visual acuity and heterophoria 

scores that are statistically equivalent to the older models. Color vision test scores for the Titmus i400 were found 

to be statistically equivalent to those of the Titmus 2A, with little or no change in failure rate. Although the color 

vision scores of the Optec 5000 were statistically equivalent to those of the Optec 2000, it failed 50% of the color 

normal subjects in the study. Conclusion. FAA approval is recommended for the Titmus i400 for use in all 

applicable aviation vision tests. Conditional approval is recommended for the Optec 5000, provided the Aviation 

Medical Examiner has an appropriate alternate color vision test should individuals be identified as color deficient 

during the certification exam. 

 

17. Key Words 18. Distribution Statement 

 

 

 

Vision, Aeromedical Certification, Vision Tester, 

Color Vision, Aviation 

Document is available to the public through the 

Defense Technical Information Service Center, Ft. 

Belvoir, VA 22060; and the National Technical 

Information Services. Springfield, VA 22161 

19. Security Classif. (of this report) 20. Security Classif. (of this page) 21. No. of Pages 22. Price 

Unclassified Unclassified 27 

Form DOT F 1700.7 (8-72) Reproduction of completed page authorized

v

ACKNOWLEDGMENTS

This research was conducted under a Cooperative Research and Development Agreement (CRDA) 

established between the FAA and the CRDA partners. The FAA Grants and Cooperative Agreements 

Center at the William J. Hughes Technical Center acted as the coordinating offi ce for the CRDA.

vii

CONTENTS

BACKGROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

METHODOLOGY . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

RESULTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

DISCUSSION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

CONCLUSIONS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

REFERENCES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Appendix A: Specifi cations for the Optec 2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . A1

Appendix B: Specifi cations for the Titmus 2A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . B1

Appendix C: Letter From the Federal Air Surgeon to Mr. Joseph Andera . . . . . . . . . . . . . . . . . . . .C1

Appendix D: Letter From the Federal Air Surgeon to Mr. Anthony Gates . . . . . . . . . . . . . . . . . . D1

Appendix E: Letter From the Federal Air Surgeon to Mr. William Broach, Jr. . . . . . . . . . . . . . . . . E1

1

EVALUATION OF NEXT-GENERATION VISION TESTERS FOR

AEROMEDICAL CERTIFICATION OF AVIATION PERSONNEL

BACKGROUND

The Federal Aviation Administration (FAA) currently 

allows Aviation Medical Examiners (AMEs) to use a variety 

of vision testing devices to evaluate a pilot applicant’s vision performance for medical certifi cation purposes. Two 

of these approved devices are the Optec 2000 vision tester 

and the Titmus 2A vision screener, both of which have 

been discontinued by their manufacturers (Stereo Optical Company, Inc., and Titmus Optical Co.). The Optec 

5000 vision tester and Titmus i400 vision screener are 

currently marketed as replacements. The manufacturers 

of these new instruments have requested FAA approval 

for use by an AME performing aeromedical certifi cation 

exams on pilot applicants.

Changes include cosmetic redesigns for both new 

testers and the use of light-emitting diodes (LEDs) and 

fl uorescent lamps, rather than incandescent light bulbs to 

illuminate the test slides, for the Optec 5000 and Titmus 

i400, respectively. All test slides and testing procedures 

for both instruments remain the same as those for the 

discontinued devices. This study compares human subject test scores obtained using the two new vision testing 

instruments with those from the respective discontinued 

models. Instrument testing included near, intermediate, 

and distant visual acuity tests, as well as heterophoria and 

color vision tests.

METHODOLOGY

All testing was performed at the Civil Aerospace 

Medical Institute, Aerospace Medical Research Division, 

in Oklahoma City, OK, by the Vision Research Team. 

All subjects read a full description of the evaluation and 

testing procedures and signed a release/consent form prior 

to participating in the study. Test subjects were assigned 

a subject number for identifi cation purposes, which was 

used for the duration of the study to ensure confi dentially. 

Prescreen tests included traditional Snellen visual acuity 

(near, intermediate, and distant), color vision (Dvorine, 

2nd Edition, Pseudo-isochromatic Plate [PIP] Test, 

and Farnsworth Dichotomous Test), and heterophoria 

evaluation (Maddox rod with Risley prisms) to ensure 

that the subject’s overall vision performance was within 

the testing limits of the instruments being evaluated. 

When necessary, test subjects wore their own refractive 

correction. Subjects with a medical history that would 

preclude them from receiving a pilot medical certifi cate 

or taking medication that could affect visual performance 

were excluded from the study. Aside from color vision 

defi ciencies, visual performance for all subjects was within 

the minimum vision requirements for Class II airmen in 

Title 14 of the Code of Federal Regulations (CFR) Part 

67, §67.203 (c) (see Table 1).

Table 1: 14 CFR 67.103(b), §67.203(c), §67.303 (d) Vision Standards (1) 

Certificate Class 

Flight Category 

First Class 

Air Transport 

Second Class 

Commercial 

Third Class 

Private 

Distant Vision 20/20 or better in each eye separately, with or 

without correction 

20/40 or better in each eye 

separately, with or without 

correction 

Intermediate

Vision

20/40 or better in each eye separately (Snellen 

equivalent), with or without correction at age 50 

and over, as measured at 32 inches 

No Requirement 

Near Vision 20/40 or better in each eye separately (Snellen equivalent), with or without 

correction, as measured at 16 inches 

Color Vision Ability to perceive those colors necessary for safe performance of airman duties 

Hyperphoria Maximum of 1 diopter No Standard 

Esophoria & 

Exophoria Maximum of 6 diopters of esophoria or exophoria No Standard 
2

The test subject population included 36 individuals 

(8 females and 28 males) that ranged in age from 18 to 

66 (average = 34.4 ± 14.2). Six subjects were 50 years 

of age or over, requiring intermediate vision testing. A 

total of 28 subjects required refractive correction, and 

two had prior laser refractive surgery. Those who used 

ophthalmic devices included 18 subjects with spectacle 

correction (8 single vision, 3 bifocal, 1 trifocal, 4 halfeye readers, and 2 progressive addition lenses) and 10 

who used contact lenses to correct their distant vision. 

Three subjects were eliminated from the study due to 

inadequate/inappropriate refractive correction (i.e., dark 

tinted lenses), the use of medication that could bias testing 

(i.e., depression and pain), and an inability to adequately 

complete all prescreening tests (i.e., fusion problems due 

to prior injury).

To compensate for any memorization due to the similarities between the tests, subjects where randomly assigned 

to one of four groups. The order of testing was divided 

such that 25% of the subjects (e.g., Group 1) were tested 

on the Optec 2000 instrument initially, followed by the 

Titmus i400, the Optec 5000, and then the Titmus 2A, 

with 10-minute rest intervals between each instrument. 

The order of testing for subjects in Group 2, Group 3, 

and Group 4 were similarly alternated so the effects of 

memorization would not favor any particular instrument. 

In addition, the left- and right-eye monocular tests were 

alternated from instrument to instrument, as was the 

direction (i.e., left to right, or right to left) in which the 

subjects were asked to read the lines of optotype. Table 

2 summarizes the testing sequence for the four groups 

of nine subjects each.

Near, distant, and intermediate visual acuity scores 

were converted from Snellen notation to decimal equivalent and then to logMAR values for statistical analysis. 

Color vision performance was measured by adding the 

number of digits correctly identifi ed out of the 8 digits 

and calculating the percentage of correct responses. The 

response order for the 6 pseudo-isochromatic plates was 

randomized in an effort to minimize memorization. 

Lateral phoria (distant) scores were recorded in 15 steps 

of 1 prism diopter (pd) each, from -7 (esophoria) to +7 

(exophoria). Vertical phoria (distant) scores were recorded 

in 7 steps of one-half pd each, from -1.5 (left hyperphoria) 

to +1.5 (right hyperphoria).

The instruments used for the testing procedures were 

provided by Stereo Optical (i.e., refurbished Optec 2000 

and new Optec 5000 vision testers) and Titmus Optical 

(i.e., refurbished Titmus 2A and new Titmus i400 vision 

screeners). The specifi cations for both Optec vision testers (2000 and 5000) are provided in Appendix A, and 

specifi cations for both Titmus vision screeners (2A and 

i400) are provided in Appendix B.

Tests on all subjects included:

Visual Acuity (monocular and binocular)

Distant

Near 

Intermediate (Subjects ≥ 50 years of age)

Color Perception (Binocular) - Distant

Pseudo-isochromatic Plates

Heterophoria - Distant

Lateral Phoria (Esophoria & Exophoria)

Vertical Phoria (Right & Left Hyperphoria) 

Test scores from each of the vision testers were collated 

and analyzed. Analysis was designed to detect whether a 

statistically signifi cant difference exists between the acuity scores obtained with the new versus the discontinued 

vision testers for each company. The Two-Factor (i.e., 

groups and devices) Analysis of Variance (ANOVA) with 

Replication was applied to the difference in logMAR acuity 

scores for (monocular and binocular) near, distant, and 

intermediate visual acuity tests. The null hypothesis states 

that the mean acuity scores for the two instruments are 

equal (Ho

: μ1 = μ2). A statistically signifi cant difference 

between the mean test scores is indicated by a probability 

value of less than 0.05 (p ≤ 0.05). The (paired) Student 

T-test was performed to determine if the differences in 

the mean color vision test scores were statistically signifi -

cant (p ≤ 0.05). Lateral and vertical phoria scores were 

analyzed using the Spearman’s Rank-Order Correlation 

•

•

•

•

•

•

•

•

•

Table 2: Summary of Testing Sequences by Subject Groups 

TEST 1 TEST 2 TEST 3 TEST 4 

GROUP 1 Optec 2000 Titmus i400 Optec 5000 Titmus 2A 

GROUP 2 Titmus i400 Optec 5000 Titmus 2A Optec 2000 

GROUP 3 Optec 5000 Titmus 2A Optec 2000 Titmus i400 

GROUP 4 Titmus 2A Optec 2000 Titmus i400 Optec 5000 
3

Test for non-parametric data. A Spearman’s coeffi cient 

(rs

) greater than rcritical (where rcritical = 0.33 and df = n - 2 = 

34) suggests a signifi cant correlation may exist (p ≤ 0.05) 

between test scores for the old and new instruments.

RESULTS

In the descriptions that follow, the average acuity 

scores and standard deviations (sd) for the various tests 

are provided in Snellen decimal form, as well as Snellen 

fraction notation (in parenthesis), with their corresponding sd converted to the approximate number of optotype. 

Figure 1 presents the average distant, near, and intermediate (monocular and binocular) visual acuity scores for 

the two Titmus vision screeners. Average acuity scores 

for the Titmus 2A ranged from 0.708 (20/28.2) to 0.963 

(20/20.8); total average = 0.862 ± 0.095 (20/23.2 ± 1.43 

optotype). Average acuity scores for the Titmus i400 

ranged from 0.793 (20/25.2) to 0.985 (20/20.3); total 

average = 0.898 ± 0.064 (20/22.3 ± 0.96 optotype).

Table 3 presents the results of the statistical analysis 

performed on the (logMAR) visual acuity scores for the 

two Titmus vision screeners. Included in Table 3 are the 

average differences in acuity scores for the old and new 

instruments, standard deviations, 95% confi dence intervals, and the probability statistics for all possible sources 

of variation (i.e., devices, groups, and between-subject by 

within-subject interactions). The difference in average acuity scores between the Titmus 2A and Titmus i400 ranged 

from -0.020 (~0.56 optotype) to 0.059 (~1.68 optotype); 

total average = 0.019 ± 0.025 (~0.55 ± 0.72 optotype). 

Statistical analysis determined there was no signifi cant 

overall difference in average acuity scores between the old 

and new Titmus devices (p > 0.05). However, there were 

signifi cant differences between the intermediate test scores 

for the two groups of older (≥ 50 years of age) subjects for 

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

Snellen Decimal (Fraction)

TITMUS 2A 0.930 0.885 0.963 0.908 0.899 0.946 0.708 0.725 0.797

TITMUS i400 0.927 0.913 0.985 0.921 0.936 0.904 0.794 0.793 0.914

Distant Right Distant Left Distant Both Near Right Near Left Near Both Inter Right Inter Left Inter Both

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

Snellen Decimal (Fraction)

TITMUS 2A 0.930 0.885 0.963 0.908 0.899 0.946 0.708 0.725 0.797

TITMUS i400 0.927 0.913 0.985 0.921 0.936 0.904 0.794 0.793 0.914

Distant Right Distant Left Distant Both Near Right Near Left Near Both Inter Right Inter Left Inter Both

Figure 1: Average acuity scores and 95% confidence intervals for the Titmus vision screeners

Table 3: Titmus Visual Acuity Statistical Analysis (logMAR) 

VISION TEST EYE Avg Diff Std Dev Conf lnt p(device) 

[df]

p(group) 

[df]

P(inter)

[df]

Right -0.002 0.066 0.022 0.905 [1] 0.124 [3] 0.800 [3] 

Left 0.014 0.074 0.024 0.479 [1] 0.563 [3] 0.890 [3] Distant 

(N = 36) Both 0.010 0.047 0.015 0.217 [1] 0.159 [3] 0.803 [3] 

Right 0.006 0.067 0.022 0.630 [1] 0.323 [3] 0.940 [3] 

Left 0.017 0.046 0.015 0.248 [1] 0.975 [3] 0.839 [3] Near 

(N = 36) Both -0.020 0.196 0.064 0.556 [1] 0.314 [3] 0.526 [3] 

Right 0.050 0.077 0.062 0.352 [1] 0.017 [1] 0.928 [1] 

Left 0.039 0.111 0.089 0.422 [1] 0.092 [1] 0.648 [1] Intermediate

(N = 6) Both 0.059 0.111 0.089 0.136 [1] 0.136 [1] 0.045 [1] 
4

the right-eye (F [1, 6] = 8.92, p = 0.017) and a signifi cant 

(between-subject [group] by within-subject [device]) interaction for the binocular intermediate test scores (F [1, 6] = 

5.62, p = 0.045) of these subjects.

Figure 2 presents the average distant, near, and intermediate (monocular and binocular) visual acuity scores 

for the two Optec vision testers. Average acuity scores for 

the Optec 2000 ranged from 0.793 (20/25.2) to 0.992 

(20/20.2); total average = 0.925 ± 0.065 (20/21.6 ± 0.97 

optotype). Average acuity scores for the Optec 5000 ranged 

from 0.743 (20/26.9) to 0.987 (20/20.3); total average = 

0.874 ± 0.096 (20/22.9 ± 1.44 optotype).

Table 4 provides the results of the statistical analysis 

performed on the (logMAR) visual acuity scores for the two 

Optec vision testers. Included in Table 4 are the average 

differences in acuity scores between the old and new instruments, standard deviations, 95% confi dence intervals, and 

the probability statistics for all possible sources of variation 

(i.e., devices, groups, and between-subject by within-subject interactions). The difference in average acuity scores 

between the Optec 2000 and Optec 5000 ranged from -0.10 

(~2.83 optotype) to 0.003 (~0.08 optotype); total average = 

-0.026 ± 0.037 (~0.74 ± 1.04 optotype). Statistical analysis 

determined there was no signifi cant difference in average 

acuity scores between the old and new Optec devices (p > 

0.05). However, there were signifi cant differences between 

the intermediate test scores for the two groups of older (≥50 

years of age) subjects for both the right (F [1, 6] = 18.76, p 

= 0.003) and left (F [1, 6] = 7.84, p = 0.026) eyes.

Figures 3 and 4 present the results of the lateral and vertical (distant) phoria tests in prism diopters for the Titmus 

2A and i400 vision screeners. Lateral phoria scores for the 

Titmus 2A ranged from -4 to 5.5 pd and averaged -0.014 

± 1.90 pd. Lateral phoria scores for the Titmus i400 ranged 

from -5 to 5 pd and averaged 0.236 ± 1.69 pd. Vertical 

phoria scores for the Titmus 2A ranged from -1 to 1 pd 

and averaged 0.042 ± 0.403 pd. Vertical phoria scores for 

the Titmus i400 ranged from -1 to 1.5 pd and averaged 

-0.194 ± 0.482 pd.

Table 5 presents the average difference in heterophoria 

scores (in prism diopters) for the Titmus 2A and i400 

vision screeners, as well as standard deviations and 95% 

Snellen Decimal (Fraction)

OPTEC 2000 0.943 0.899 0.992 0.956 0.967 0.979 0.857 0.793 0.935

OPTEC 5000 0.930 0.905 0.987 0.957 0.970 0.834 0.785 0.754 0.743

Distant Right Distant Left Distant Both Near Right Near Left Near Both Inter Right Inter Left Inter Both

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

Snellen Decimal (Fraction)

OPTEC 2000 0.943 0.899 0.992 0.956 0.967 0.979 0.857 0.793 0.935

OPTEC 5000 0.930 0.905 0.987 0.957 0.970 0.834 0.785 0.754 0.743

Distant Right Distant Left Distant Both Near Right Near Left Near Both Inter Right Inter Left Inter Both

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

0.6

(20/33.3)

0.7

(20/28.6)

0.8

(20/25)

0.9

(20/22.2)

1.0

(20/20)

1.1

(20/18.2)

Figure 2: Average acuity scores and 95% confi dence intervals for the Optec vision testers

Table 4: Optec Acuity Statistics (logMAR)

VISION TEST EYE Avg Diff Std Dev Conf Int P(device) [df] p(group) [df] p(inter) [df] 

Right -0.006 0.043 0.014 0.985 [1] 0.337 [3] 0.745 [3] 

Left 0.003 0.035 0.011 0.862 [1] 0.623 [3] 0.840 [3] Distant 

(N = 36) Both -0.002 0.014 0.005 0.131 [1] 0.456 [3] 0.564 [3] 

Right 0.000 0.029 0.009 0.630 [1] 0.323 [3] 0.940 [3] 

Left 0.001 0.047 0.015 0.248 [1] 0.975 [3] 0.839 [3] Near 

(N = 36) Both -0.070 0.273 0.089 0.556 [1] 0.314 [3] 0.526 [3] 

Right -0.039 0.050 0.040 0.242 [1] 0.003 [1] 0.420 [1] 

Left -0.022 0.095 0.076 0.596 [1] 0.026 [1] 0.195 [1] Intermediate

(N = 6) Both -0.100 0.140 0.112 0.169 [1] 0.393 [1] 0.991 [1] 
5

Table 5: Titmus Heterophoria Statistics 

PHORIA 

TEST Avg Diff Std Dev 95% Confidence Interval rs rs

2 t P(t) 

LATERAL -0.250 0.952 -0.572 < -0.250 < 0.072 0.856 0.732 9.63 < 1X10-6

VERTICAL -0.153 0.334 -0.266 < -0.153 < -0.040 0.754 0.569 6.70 < 1X10-6

Figure 3: Lateral phoria scores for the Titmus vision screeners (greater or less than 

± 6 pd fails)

Figure 4: Vertical phoria scores for the Titmus vision screeners (greater or less than 

± 1 pd fails)
6

confi dence intervals. Also provided are the Spearman coeffi cients (rs

 and rs

2

), approximated t-statistic, and probability 

values for the Titmus (distant) heterophoria scores. The 

average difference in the (lateral and vertical) phoria scores 

for the two instruments was relatively small ( – 0.3 pd), 

but lateral phoria scores exhibited greater variability. Both 

Spearman’s coeffi cients (rs

) were positive and greater than 

r

critical = 0.33 (df = 34), indicative of signifi cant correlations 

between test scores. Both lateral and vertical p-values were 

considerably less than 0.05, indicating strong (rs

 > 0.67), 

positive correlations between the phoria scores for the old 

and new Titmus instruments.

Figures 5 and 6 present the results of the lateral and 

vertical (distant) phoria tests in prism diopters for the Optec 

2000 and 5000 vision testers. Lateral phoria scores for the 

Optec 2000 ranged from -5 to 7 pd and averaged -1.25 ± 

Figure 5: Lateral phoria scores for the Optec vision testers (greater or less than 

± 6 pd fails)

Figure 6: Vertical phoria scores for the Optec vision testers (greater or less than ± 1 pd fails)
7

2.71 pd. Lateral phoria scores for the Optec 5000 ranged 

from -6 to 6 pd and averaged 1.17 ± 2.30 pd. Vertical 

phoria scores for the Optec 2000 ranged from -1 to 1 pd 

and averaged -0.069 ± 0.43 pd. Vertical phoria scores for 

the Optec 5000 ranged from -1.25 to 1 pd and averaged 

-0.007 ± 0.42 pd.

Table 6 presents the average difference in heterophoria 

scores (in prism diopters) for the Optec 2000 and 5000, as 

well as standard deviations and 95% confi dence intervals 

of the difference in Optec (lateral and vertical) phoria 

scores in prism diopters. Also provided are the Spearman 

Coeffi cients (rs

 and rs

2

), approximated t-statistic, and 

probability values for the Optec (distant) heterophoria 

scores. The average difference in the (lateral and vertical) phoria scores for the two instruments was relatively 

small (< ± 0.1 pd), but lateral phoria scores exhibited 

greater variability. Both Spearman coeffi cients (rs

) were 

positive and greater than rcritical = 0.33 (df = 34), indicative of signifi cant correlations between test scores. Both 

lateral and vertical p-values were considerably less than 

0.05, indicating strong (rs

 > 0.67) positive correlations 

between the phoria scores for the old and new Optec 

instruments.

Figure 7 presents color vision test scores as the percent 

of correctly identifi ed digits (out of 8 possible) for the 

Titmus instruments. Note that the average color vision 

scores were marginally higher from the new Titmus device 

for both color defective and color normal test subjects.

Table 7 presents the average, standard deviations, 95% 

confi dence intervals of the differences in color vision 

scores for the Titmus instruments, and the probability 

values, as determined by the (paired) Student T-test. The 

number of subjects to pass or fail the Titmus 2A and i400 

color vision tests are also presented by subject population. Only one color normal subject failed the Titmus 

2A color vision test, while none failed on the Titmus 

i400 and both devices failed all color defective subjects. 

All probability values indicate the differences in average 

color vision test scores for the two instruments are not 

statistically signifi cant (p > 0.05).

Color vision test scores for the Optec instruments are 

presented in Figure 8. Note that the average color vision 

scores from the old Optec device were higher for color 

normal test subjects.

Table 8 presents the average, standard deviations, 95% 

confi dence intervals of the differences in color vision 

scores for the Optec instruments, and the probability 

values, as determined by the (paired) Student T-test. 

The number of subjects to pass or fail the Optec 2000 

and 5000 color vision tests are also presented by subject 

population. The color vision scores for color normal 

subjects were signifi cantly (p < 0.05) higher using the 

Table 6: Optec Heterophoria Statistics 

PHORIA TEST Avg Diff Std Dev 95% Confidence Interval rs rs

2 t P(t) 

LATERAL 0.083 1.279 -0.349 < 0.083 < 0.516 0.888 0.790 11.31 < 1X10-6

VERTICAL -0.063 0.183 -0.124 < -0.063 < -0.001 0.902 0.814 12.21 < 1X10-6

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

Percentage Correct

Titmus 2A 75.7% 99.0% 29.2%

Titmus i400 77.1% 100.0% 31.3%

All Subjects Color Normal Color Defective

20%

30%

40%

50%

60%

70%

80%

90%

100%

110%

Percentage Correct

Titmus 2A 75.7% 99.0% 29.2%

Titmus i400 77.1% 100.0% 31.3%

All Subjects Color Normal Color Defective

Figure 7: Average color vision scores and 95% confi dence intervals for the 

Titmus vision screeners (< 100% fails for pilot certifi cation purposes)
8

Optec 2000 than those obtained with the Optec 5000 

vision tester. Six color normal subjects failed at least one 

response on the Optec 2000, while 12 failed at least one 

response on the Optec 5000 instrument.

DISCUSSION

Since November 1985, the Titmus 2A vision screener 

and Optec 2000 vision tester have been approved for use 

by AMEs to test the visual performance qualifi cations of 

applicants seeking an airman medical certifi cate (see Appendices C and D). Approval for both devices was based 

on the manufacturers’ success in meeting FDA requirements and FAA assessment that the newer vision testers 

were “substantially equivalent” to the previously approved 

Titmus OV7-M. How this equivalence was determined 

is not known, as there is no documentation to indicate 

that independent testing was performed. FAA approval 

for intermediate visual acuity testing of subjects 50 years 

of age and older, in accordance with the revised medical standard, was granted for the Titmus 2A and earlier 

models of that series in May 1996 (see Appendix E). No 

evidence of a similar approval for the Optec devices was 

found. Although a 1990 study performed for the military 

by McAlister and Peters found the Titmus II’s acuity and 

color vision test scores to be statistically equivalent when 

compared to clinical test scores, similar comparison found 

a signifi cant difference in heterophoria scores (2).

To ensure the validity and repeatability of test results, 

recommended standards for vision testing are put forth 

by several esteemed organizations. A number of these 

standards are widely accepted and generally adhered to in 

clinical testing and in the development of vision testers. 

Examples of these recommendations include: standards 

20%

30%

40%

50%

60%

70%

80%

90%

100%

Percentage Correct

Optec 2000 73.3% 96.4% 27.1%

Optec 5000 69.8% 91.1% 27.1%

All Subjects Color Normal Color Defective

20%

30%

40%

50%

60%

70%

80%

90%

100%

Percentage Correct

Optec 2000 73.3% 96.4% 27.1%

Optec 5000 69.8% 91.1% 27.1%

All Subjects Color Normal Color Defective

Figure 8: Average color vision scores and 95% confidence intervals for the 

Optec vision testers (< 100% fails for pilot certification purposes)

Table 7: Titmus Color Vision Statistics 

Pass Fail 

Subject

Population Avg Diff Std Dev CI (+/-) p(t) 2A

i400

2A

i400

All Subjects 

(n=36) -1.39% 5.73% 1.87% 0.160 23

24

13

12

Color

Normal

(n=24)

-1.04% 5.00% 2.00% 0.328 23

24

1

0

Color

Defective

(n=12)

-2.08% 6.91% 3.91% 0.339 0

0

12

12
9

for eye chart luminance (avg. = 160 cd/m2 – range: 80 

- 320 cd/m2

), color temperature (between 2500K and 

7000K), characteristics of target letters (National Research 

Council, 1980) (3), and letter contrast (ISO 8596 [1994], 

ANSI Z80.21-1992 [R2004]) (4,5). Visual acuity test 

slides generally conform to these recommended standards 

and have remained unchanged for all Titmus and Stereo 

Optical instruments. All instruments utilize slides that 

are photographic reproductions of Snellen eye charts to 

measure distant, intermediate, and near acuity. The slides 

are essentially abbreviated versions of the Early Treatment 

for Diabetic Retinopathy Study (ETDRS) (6). Figure 9 

provides a subject’s view of the (left monocular) distant 

acuity test slide for each of the four instruments.

Several of the recommended standards for vision testers 

post-date the initial FAA approval of the older devices; 

therefore, they were not required to meet those standards. 

Similarly, the determination of substantial equivalence 

does not require the new devices to conform to current 

recommended standards for vision testing. However, 

luminance, target contrast, and optotype were evaluated for both new instruments and found to be within 

minimum tolerances. The color temperature and color 

rendering of the light sources could not be measured with 

the equipment available.

A standard illuminant C source has a color temperature 

of 6700K that is considered ideal for color vision testing 

(7). Illuminant C is a bluish-white light corresponding 

to the north sky on an overcast day in the northern 

hemisphere (8). As Figure 9 illustrates, the incandescent 

lighting of the older devices appears warmer compared 

to the cooler, bluish lighting (fl uorescent and LED) of 

the new models.

The average visual acuity scores of the new devices 

compared favorably with those of the older models. However, 7 subjects (5 subjects ≥ 50 years of age) experienced 

diffi culty in maintaining fusion when binocular near 

and intermediate testing was performed with the new 

devices (i.e., 6 subjects on the Optec 5000; 1 subject on 

both the Optec 5000 and Titmus i400). Only 2 of these 

individuals could not achieve adequate fusion to complete 

the near visual acuity test (i.e., 1 subject on the Optec 

5000 and the other on both the Optec 5000 and Titmus 

i400). This fusion problem may be due to induced prism 

effects from the instruments' lenses.

Table 8: Optec Color Vision Statistics 

Pass Fail 

Subject

Population Avg Diff Std Dev CI (+/-) p(t) 2000

5000

2000

5000

All Subjects 

(n=36) 3.47% 7.68% 2.51% 0.010 1812

18

24

Color

Normal

(n=24)

5.21% 8.17% 3.27% 0.005 18

12

6

12

Color

Defective

(n=12)

0.00% 5.33% 3.02% 1.00 0

0

12

12

Figure 9: Photos of target slides taken through the optics of each device with a Nikon E8700 digital camera. 

From left to right: Optec 2000, Optec 5000, Titmus 2A, and Titmus i400. (Note: These images are to 

demonstrate color differential, not to accurately depict the subject’s view of the test slides.)
10

It should be noted that these results would not have 

medically disqualifi ed these subjects for aeromedical 

certifi cation of pilots, since all subjects met the FAA 

standard for monocular intermediate and near vision. 

These subjects had no fusion problems during prescreening or when tested on the older vision screening devices. 

Even with these anomalies, statistical analysis indicated 

non-signifi cant (p > 0.05) differences in average acuity 

scores between the old and new instruments.

There were signifi cant differences between the group 

acuity scores for the Titmus monocular (right-eye) intermediate test (F [1, 6] = 8.92, p = 0.017) and signifi cant 

between-subject and within-subject interactions (F [1, 6] = 

5.62, p = 0.045) for the binocular intermediate test (Table 

3). Similarly, there were signifi cant differences between 

the group scores in the monocular (right- and left-eye) 

intermediate tests (F [1, 6] = 18.76, p = 0.003 and F [1, 

6] = 7.84, p = 0.026, respectively) for the Optec units 

(Table 4). These fi ndings may be the result of practice 

effects (or memorization) introduced due to the small 

number of subjects requiring intermediate vision testing 

(n = 6), which did not allow for an even distribution of 

subjects between the 4 test groups. However, follow-up 

analysis using the paired Student T-test confi rmed the 

non-signifi cant fi ndings of the ANOVA tests for the difference between the intermediate acuity scores for the old 

and new instruments of both manufacturers.

Phoria tests measure the latent or relative deviation 

between the eyes that occurs when fusion is interrupted. 

It is often described as the resting position of the eyes. A 

phoria does not exclusively apply to one eye or the other 

and may be lateral (esophoria for “in,” or exophoria for 

“out”) and/or vertical (“right” or “left” hyperphoria). 

First- and Second-Class pilot applicants for aeromedical 

certifi cation with more than 1 pd of hyperphoria and/or 

6 pd of esophoria or exophoria are not disqualifi ed but 

would be referred to an eyecare specialist for further 

testing to determine if there is bifoveal fi xation and an 

adequate vergence-phoria relationship. While all subjects 

passed the prescreening (Maddox rod) phoria test, two 

individuals did not meet the certifi cation standard when 

tested on these instruments. One subject’s score was 

greater than 1 pd of right hyperphoria (1.5 pd) on the 

Titmus i400 and another subject scored greater than 6 

pd of exophoria (+ 7 pd) on the Optec 2000. However, 

statistically, the (lateral and vertical) phoria scores for the 

old and new devices compared favorably, according to 

the Spearman Test. All four Spearman’s coeffi cients (rs

) 

were greater than rcritical = 0.33, indicative of signifi cant 

(p < 0.05) correlations between test scores for the old 

and new Titmus and Optec instruments.

The CFR state that pilot applicants must demonstrate 

the “ability to perceive those colors necessary for the safe 

performance of airman duties” (9). AMEs must administer 

color vision screening tests as part of the certifi cation exam 

to identify those that may not meet this requirement. 

Defective color vision is characterized by abnormal color 

matching and a loss of color discrimination. Dichromats 

are color defectives that lack one of the three photopigments responsible for color discrimination normally found 

in the cone receptors of the retina. Anomalous trichromats 

have all three photopigments, but one is abnormal. Color 

defi ciencies can be further categorized as follows: protans 

either have a loss of the long wavelength-sensitive cones 

(protanope) or have long wavelength-sensitive cones 

whose spectral response is shifted towards the middle 

wavelength-sensitive cones (protanomalous); deutans 

either have a loss of the middle wavelength-sensitive 

cones (deuteranope) or have middle wavelength-sensitive cones whose spectral response is shifted towards 

the long wavelength-sensitive cones (deuteranomalous); 

and tritans either lack the short wavelength-sensitive 

cones (tritanope) or have only a limited number of short 

wavelength-sensitive cones responding (tritanomalous). 

Most color vision tests cannot distinguish between the 

dichromats and anomalous trichromats, so the terms 

protan, deutan, and tritan defi ciency are used. A range 

of severity is found in each type of defi ciency (8).

Prescreening color vision tests included the Dvorine 

PIP (plates 1-15) and the Farnsworth Panel D-15. The 

Dvorine test is widely used as a screening test for congenital red-green defi ciency. Accuracy for identifying 

color-defi cient individuals is reportedly about 95% (10). 

The FAA standard for the Dvorine PIP test requires the 

subject to correctly identify at least 8 of the 15 plates to 

qualify for certifi cation. All 24 subjects that claimed to 

have normal color vision easily met the FAA standard; 

however, 1 subject misidentifi ed 3 plates and would 

have been considered mildly color defi cient based on the 

Dvorine test criteria (i.e., 0 to 2 plates missed) (11). The 

fi rst plate is for demonstration and is recognized by all 

subjects. The two most common types of color defi cits 

are detected with plates 6 and 7 (i.e., protan and deutan, 

respectively). However, there is some thought that these 

plates have a low effi ciency rate (10). In this study, the 

Dvorine PIP test correctly identifi ed the 12 color- defective 

(CD) subjects, classifying 3 as severely defective and 9 

as moderately defective. Of the 12 CD subjects, 5 were 

categorized with both red and green (protan/deutan) 

defi cits, 6 with green (deutan), and 1 could not be categorized with the Dvorine PIP test.

The D-15 test is not used to qualify pilot applicants 

for aeromedical certifi cation. Scoring is designed to differentiate between subjects with moderate-to-severe color 

defi ciencies and those with normal color vision (12). The 

D-15 requires the subject to arrange 15 colored caps, or 
11

“buttons,” in order according to their hue. An observer 

scores the results using numbers on the bottom of the 

caps to trace a circular diagram that should correspond 

to a steady stepwise progression in hue. If isochromatic 

errors are made by the test subject, they give rise to lines 

that cross the diagram where buttons belonging to the 

opposite side of the hue circle were incorrectly placed 

next to each other. The degree of defi ciency is determined 

by the number of isochromatic confusions made by the 

subject’s arrangement of the buttons (10). Two or more 

errors results in a test failure. All 24 subjects that claimed 

to have normal color vision correctly positioned the 15 

colored caps. Of the 12 CD subjects, 10 failed the D15 test and 2 passed, indicating mild-to-moderate color 

defi ciency. Of the 10 subjects that failed, the Dvorine 

classifi ed 4 subjects as being both deutans and protans, 

while the D-15 classifi ed them as 3 protans and 1 deutan. Agreement between the two tests was found for 5 

of the 10 subjects (all classifi ed as deutans), with the 1 

remaining subject classifi ed as a deutan by the Dvorine 

and as an anomalous trichromat by the D-15. These 

results suggest that the classifi cation of color defi ciency 

can vary between the Dvorine and D-15 test.

According to the instructions for the Optec and Titmus 

instruments, both classify the correct identifi cation of all 

8 digits on the 6 PIPs (A – F) as normal color vision (see 

Figure 10), while correctly reading at least 5 digits indicates 

a reading 4 or fewer digits correctly results in test failure. 

For the purpose of aeromedical certifi cation of pilots, an 

error on any of the 8 digits results in failure on any of 

the instruments under evaluation. Although one color 

normal (CN) subject failed to correctly identify 2 digits 

on the Titmus 2A color vision test, statistical analysis 

found no signifi cant differences (p > 0.05) between the 

average scores of the old and new Titmus instruments 

for both the CN and CD subjects. Both old and new 

Optec instruments correctly identifi ed all 12 CD subjects; 

however, the Optec 2000 failed 6 of the 24 CN subjects 

(25% failure rate), and the Optec 5000 failed 5 of those 

6 subjects, as well as an additional 7 CN subjects, for 

a total of 12 (50% failure rate). While the fi ndings for 

the Optec 2000 were not totally unexpected, given its 

high rate of false positives documented in previous FAA 

reports (13,14), the 50% false-positive rate exhibited by 

the Optec 5000 was troubling. Analysis indicated that 

the color vision test scores for CN subjects provided by 

the Optec 5000 were signifi cantly (p = 0.005) poorer 

than those obtained with the Optec 2000. This does not, 

however, indicate that the instruments are not equivalent 

based on the pass/fail criteria of the manufacturer, since 

all CN subjects who failed would be considered only 

mildly color defi cient (i.e., 7 to 5 correct responses). 

Overall, color vision test scores provided by the old and 

new Optec devices demonstrated a strong positive correlation using the Spearman Test (rs = 0.88) when CN 

and CD scores were analyzed together.

All 13 CN subjects who failed the color vision test on 1 

of the 3 devices had passed both prescreening color vision 

tests, but 3 of these subjects incorrectly identifi ed 1 to as 

many as 3 digits on the Dvorine PIP test. These 13 CN 

subjects had an average age of 41.7 (std dev ± 18 years, 

range: 20 to 66 years of age). While 11 CN subjects missed 

only 1 digit on any one instrument, 2 subjects missed 2 

digits on the Optec 5000. Digits were most frequently 

missed on the D plate, followed by the “diagnostic” C 

plate. The diagnostic C plate results categorized 3 of 

the CN subjects as being green (deutan) color defi cient, 

2 red (protan), and 2 green/red (deutan/protan). The 

remaining 6 CN subjects could only be categorized as 

mildly color defi cient.

While vision testers can make the task of examining 

patients more convenient, the examiner must be well 

acquainted with the instrument and its limitations. The 

following are general recommendations that could be 

helpful when using such instruments.

When setting up a new instrument, perform all 

test procedures to verify the instrument is working 

correctly.

Confi rm that the lenses for intermediate visual acuity 

testing are of the correct power.

1.

2.

Figure 10: Photos of color vision test slides taken through the optics of each device with a Nikon E8700 digital 

camera. From left to right: Optec 2000, Optec 5000, Titmus 2A, and Titmus i400. (Note: These images are to 

demonstrate color differential, not to accurately depict the subject’s view of the test slides.)
12

Instrument should be placed in an area where lighting can be controlled (e.g., dimming overhead lights 

during testing).

Some instruments require a period to warm up for 

correct illumination before use.

If corrective lenses are to be worn during testing, 

check them for cleanliness and that the subject can 

position their head comfortably in the instrument 

with the spectacles on.

Subjects should be seated comfortably with forehead 

fi rmly against the headrest (instrument, seat, or 

table may have to be adjusted up or down). Some 

instruments require that the forehead be pressed 

fi rmly against the headrest to turn on the illumination system. Others require that forehead be lightly 

touching the headrest so that lights on the side of 

the instrument can detect that the subject’s head 

is correctly positioned. Proper positioning of the 

head is critical for binocular near and intermediate 

vision tests.

While performing distant visual acuity, have the 

subject read letters in the far right column for the 

right eye, those in the far left column for left eye, 

and the middle column for binocular testing. If the 

subject reports that visual acuity charts are not clear 

while performing binocular testing, fi rst check to 

see that you have the correct chart selected. If the 

subject still has diffi culty, reposition subject's head 

and try again. Finally, suggest the subject close both 

eyes, open one, and then open the other eye, as this 

may help in fusion of the binocular charts.

While performing near testing, some instruments 

require the subject to look downward to see near 

acuity charts. Those wearing bifocal correction should 

position themselves to access the bifocal portion of 

their lenses.

If the subject requires intermediate visual acuity testing, the instrument must be set for distant vision, 

and intermediate lenses must be placed in a slot on 

top of the instrument. Those wearing intermediate 

correction should position themselves to access the 

appropriate portion of their lenses.

While testing color vision, the subject should be 

made aware that numbers may not be present on 

all test plates. Seeing no digits on a color plate is an 

acceptable response.

For lateral and vertical phoria testing, the instructions 

may suggest switching “on” the right eye fi rst and 

having the subject report how many notes are visible. 

Then, after switching “on” the left eye, the subject 

reports to which note the arrow points or which note 

the red line intersects. Other instruments require that 

3.

4.

5.

6.

7.

8.

9.

10.

11.

both right and left eye be switched “on” simultaneously. To assist the subject if he or she reports that 

the arrow or line appears to move, switch “off” left 

eye (i.e., arrow/red line will disappear). When the 

left eye is switched back “on,” have subject identify 

to which note the arrow or red line fi rst points.

At the end of each day, clean instrument viewing 

lenses carefully, cover the instrument to keep dust 

from collecting, and clean and store intermediate 

lenses.

When the illumination lights require replacement, 

check the instruction manual for the correct replacement procedure.

CONCLUSIONS

The results of this study indicate that, although fusion 

problems were encountered in the binocular near and 

intermediate visual acuity tests on the new models, both 

new instruments provided visual acuity and heterophoria 

scores that are statistically equivalent to those of their 

predecessors. Color vision scores for the new Titmus i400 

were found to be statistically equivalent to those provided 

by the discontinued Titmus 2A. Therefore, FAA approval 

is recommended for Titmus i400 for testing visual acuity, 

heterophoria, and color vision requirements of pilot applicants seeking aeromedical certifi cation. Although the 

Optec 5000 met the criterion for both visual acuity and 

heterophoria testing, it did not demonstrate statistical 

equivalence with the earlier model for color vision testing. 

Based on the FAA criteria for pass/fail on the color vision 

test, the Optec 2000 vision tester failed 25% of the CN 

subjects tested, while the Optec 5000 failed 50%. The 

reasons for these high failure rates are unclear. However, 

possible causes include inaccurate photographic reproduction of PIP test slides, combined with the poor color 

rendering of the LED light source (8,15). Reproduction 

of test slides using an imprecise color gamut that differs 

signifi cantly from that of the original PIP could affect 

the accuracy and consistency of test results. In addition, 

inappropriate lighting could be a confounding infl uence 

by introducing variations in luminance, color temperature, and color rendering that may result in test patterns 

appearing less recognizable to color normal subjects. 

Based on these fi ndings, conditional FAA approval is 

recommended for the Optec 5000, provided the AME 

has an alternate color vision test available (e.g., Dvorine 

PIP), should individuals be identifi ed as color defi cient 

during the certifi cation exam.

Note: The most recent version of the “Guide for 

Aviation Medical Examiners” lists the Titmus i400 as 

an approved vision tester for visual acuity, heterophoria 

12.

13.
13

and color vision testing. The Optec 5000 is listed as an 

approved vision tester for visual acuity and heterophoria 

testing, but it is listed as an unapproved instrument for 

color vision testing (9).

REFERENCES

1. Code of Federal Regulations. Title 14 of the Code 

of Federal Regulations (CFR) Part 67, §67.103(b), 

§67.203(c), §67.303(d). Washington, DC: U.S. 

Government Printing Office, Jan. 1, 2008.

2. McAlister WH, Peters JK. The validity of the Titmus 

vision testing results. Military Medicine. 1990 Sep; 

155(9):396.

3. Recommended standard procedures for the clinical measurement and specification of visual acuity. 

Report of working group 39. Committee on Vision. Assembly of Behavioral and Social Sciences, 

National Research Council, National Academy of 

Sciences, Washington, DC. Adv Ophthalmol 1980; 

41:103–48.

4. ISO 8596:1994, Ophthalmic optics -- Visual acuity 

testing -- Standard optotype and its presentation. 

International Organization for Standardization / 

01-Feb-1994 / 4 pages. Available at URL: http://

webstore.ansi.org/RecordDetail.aspx?Sku=ISO

%208596:1994&PageType=0 (Accessed: 20 Jan. 

2009).

5. ANSI Z80.21 – 1992 [R2004] Ophthalmics - Instruments - General-Purpose Clinical Visual Acuity 

Charts. American National Standards Institute. 

Available at URL: http://webstore.ansi.org/Record

Detail.aspx?sku=ANSI+Z80.21-1992+(R2004) 

(Accessed: 20 Jan. 2009).

6. Ferris FL, Kassoff A, Bresnick GH, and Bailey IL. 

New visual acuity charts for clinical research. Am 

J Ophthalmol 1982 Jul; 94(1), 91-6.

7. CIE (1932). Commission internationale de 

l’Eclairage proceedings, 1931. Cambridge: Cambridge University Press.

8. Birch J. Diagnosis of defective colour vision. In: 

Birch J. Diagnosis of defective colour vision 2nd Ed. 

London: Butterworth-Heineman; 2001:5-29.

9. Examination Techniques Item 52. Color Vision. 

The Guide for Aviation Medical Examiners. www.

faa.gov/about/office_org/headquarters_offices/

avs/offices/aam/ame/guide/ (Accessed: 11 Apr. 

2008).

10. Birch J. Tests for defective colour vision. In: Birch 

J. Diagnosis of defective colour vision 2nd Ed. 

London: Butterworth-Heineman; 2001:61-2.

11. Devorine I. Estimating the degree of color vision 

defect: Quantification classification table. Dvorine 

Pseudo-Isochromatic Plates 2nd Ed. New York, NY: 

The Psychological Corporation, 1953.

12. Farnsworth D. The Farnsworth Dichotomous test 

for color blindness. New York, NY: The Psychological Corporation, 1947.

13. Mertens HW. Evaluation of functional color vision 

requirements and current color vision screening 

tests for air traffic control specialists. Washington, 

DC: Department of Transportation/Federal Aviation Administration: 1990. Report No. DOT/FAA/

AM-90/9.

14. Mertens HW, Milburn NJ. Validity of clinical 

color vision tests for air traffic control specialists. 

Washington, DC: Department of Transportation/

Federal Aviation Administration: 1992. Report No. 

DOT/FAA/AM-92/29.

15. Hashimoto K, Yano T, Shimizu M, Nayatani Y. New 

method for specifying color-rendering properties 

of light sources based on feeling of contrast. Color 

Res Appl 2007 Aug; 32(5):361-71.

A1

APPENDIX A

SPECIFICATIONS FOR OPTEC 2000

1. EXTERNAL DESIGN:

 a. Occupy two square feet of space.

 b. Use on table or counter top.

 c. Lightweight and transportable (15 lbs.) with slides.

 d. Convenient built in handle.

 e. The housing is fl ame retardant, non-conductive material. Made from high-impact ABS 

plastic, which can be cleaned with mild soap and water.

 f. Dimensions: 15-1/2”-H, Base 9-1/2”-W x 14-1/4”-L.

2. ELECTRICAL:

 a. 120 VAC or 220 VAC confi guration. 0.2 AMPS/24 WATTS

 b. Push button switch controls.

 c. Headrest switch activates internal lighting when subject’s head is in proper position.

 d. Non-Perimeter model is UL Listed. Ref. UL No. E95176 (N).

3. DESIGN FEATURES:

 a. Near point test allows the patient to use normal bifocal lens without having to move their 

head.

 b. Observation windows on both the right and left sides of instrument enables test administrator easy access to point at tests for clarifi cation when needed.

 c. Bulbs replaced easily by fi eld personnel.

 d. No gears in unit.

 e. Confi dential testing. Only subject and administrator can observe test and results.

 f. Evenly distributed illumination over entire test pattern. Color corrected light source.

 g. Positive occlusion of right or left eye independently of each other by electronic control.

 h. Lens system capable of Far Point, Near Point and Intermediate Point testing.

 i. Disposable headrest tissues for maximum hygienic conditions.

 j. Faceplate will accommodate contemporary eyeglasses and bifocal frames.

 k. Locking adjustment for height positioning.

4. TEST:

 a. Capable of presenting up to 12 tests on a rotating drum.

 b. Field personnel can make installation or replacement of slides quickly and easily.

 c. Slides are manufactured from high quality, photographic fi lm. Sealed between two glass 

plates protecting it from moisture and dust.

 d. Slides are easily cleaned with glass cleaner.

 e. Photographically reproduced tests are transilluminated rather than using refl ective 

light,eliminating any possible surface glare.

 f. Slides to test the following functions can be supplied: Monocular Acuity, Binocular Acuity, Color, Perception, Depth Perception and Muscle Balance, and Near and Far Point 

positions.
A2

APPENDIX A (Continued)

SPECIFICATIONS FOR OPTEC 5000

1. EXTERNAL DESIGN:

 a. Occupy 2 square feet of space.

 b. Use on table or counter top.

 c. Lightweight and transportable (15 lbs.) with slides.

 d. Convenient built in handle.

 e. The housing is fl ame retardant, non-conductive material, molded from high impact ABS 

plastic, which can be cleaned with mild soap and water.

 f. Dimensions: 18”-H, Base 11”-W x 15-1/2”-L.

2. ELECTRICAL:

 a. Input:100-240V ~ 1.6A Max, 50-60Hz

 b. Output: +24Vָָָ 2.1A

 c. Output Power: 50W MAX.

 d. UL 60601-1/CAN/CSS C22.2 NO. 601.1

 e. Push button switch controls.

 f. Headrest switch activates internal lighting when subject’s head is in proper position.

 

3. DESIGN FEATURES:

 a. Near point test allows the patient to use normal bifocal lens without having to move their 

head.

 b. Observation windows on both the right and left sides of instrument enables test administrator easy access to point at tests for clarifi cation when needed.

 c. LED Illumination – no bulb replacement necessary.

 d. No gears in unit.

 e. Confi dential testing. Only subject and administrator can observe test and results.

 f. Evenly distributed illumination over entire test pattern. Color corrected light source.

 g. Positive occlusion of right or left eye independently of each other by electronic control.

 h. Lens system capable of Far Point, Near Point and Intermediate Point testing.

 i. Disposable headrest tissues for maximum hygienic conditions.

 j. Faceplate will accommodate contemporary eyeglasses and bifocal frames.

 k. Locking adjustment for height positioning.

4. TEST:

 a. Capable of presenting up to 12 tests on a rotating drum.

 b. Field personnel can make installation or replacement of slides quickly and easily.

 c. Slides are manufactured from high quality, photographic fi lm, sealed between two glass 

plates, protecting them from moisture and dust.

 d. Slides are easily cleaned with glass cleaner.

 e. Photographically reproduced tests are transilluminated rather than using refl ective light, 

eliminating possible surface glare.

 f. Slides to test the following functions can be supplied: Monocular Acuity, Binocular Acuity, 

Color Perception, Depth Perception and Muscle Balance, and Near and Far Point positions.

5. WARRANTY:

 a. Two years parts and labor. 
A3

APPENDIX A (Continued)

B1

APPENDIX B

SPECIFICATIONS FOR TITMUS 2A
B2

APPENDIX B (Continued)

SPECIFICATIONS FOR TITMUS i400
B3

APPENDIX B (CONTINUED)

C1

APPENDIX C

D1

APPENDIX D

E1

APPENDIX E