Table 8

Validity of Color Vision Selection Tests for Prediction of
Performance on Tests Radar-L and Radar-S

LARGE TARGETS SMALL TARGETS
Error Rate (%) Error Rate (%:
False Validity False Validity
TEST Miss Alarm (Kappa) Miss Alarm (Kappa)
Anomaloscope (Pass Normai 5.8 18.4 74 23.9 2.6 -65

or Mild)
FAA-Accepted Tests (Class |}

AOC (15-Piate) 4.9 22.7 -70 20.6 7.9 -67
Richmond 5.8 29.6 71 21.3 4.5 69
AOC (18-Plate) 3.9 24.8 -69 20.0 11.2 -65
AOC-HRR 5.8 19.9 72 21.9 4.5 -69
Ishihara (14-Plate) 5.8 17.7 75 23.2 3.4 68
Ishihara (16-Plate) 5.8 18.4 74 23.2 4.5 -67
Ishihara (24-Plate) 5.8 16.3 76 23.9 2.2 -68
Ishihara (38-Plate) 5.8 16.3 76 23.9 2.2 68
Dvorine 5.8 18.4 74 22.6 3.4 .69
Titmus Tester 1.9 58.9 35 9.7 49.4 44
Titmus I Tester 1.2 54.6 40 9.7 42.7 -50
OPTEC 2000 5.8 39.7 51 17.4 28.1 54
Keystone 5.8 22.0 -70 20.6 5.6 -69
Farnsworth Lantern 8.7 10.0 81 30.5 1.4 -62

*U.S. GOVERNMENT PRINTING OFFICE: 1992-761-068/6f/033
A-S


VALIDITY OF CLINICAL COLOR VISION TESTS FOR
AIR TRAFFIC CONTROL SPECIALISTS

INTRODUCTION

The requirement for accurate color discrimination
abilicy has been established (U.S. Government, Office of
Personnel Management) for Air Traffic Control Special-
ists (ATCSs). This is necessary because of color-coding
of critical information for several tasks at en route
centers, terminal air traffic control (ATC) facilities, and
flight service stations (FSSs) of the Federal Aviation
Administration. Those tasks were identified in ATCS
job analyses and field studies (Lahey, Veres, Kuyk, Clark,
and Smith, 1984a, 1984b) and were listed by Mertens
and Milburn (1992). Four of those tasks involve color
coding as a primary, non-redundant cue. Those tasks
include identification and discrimination of color in
reading flight progress strips, identifying aircraft and
their direction of movement from navigation lights at
night, use of the Aviation Signal Light to direct aircraft
with radio failure, and use of color weather radar at FSSs.

Therefore, the safety factor associated with air
traffic control work necessitates accurate color identifi-
cation. Errors in color identification or discrimination in
these :asks have the potential of placing pilots, passen-
gers, and their aircraft in danger. Because the need for
accurate color vision has been established and is sup-
ported by research findings (Adams and Tague, 1985;
Kuyk, et al., 1986, 1987; Mertens, 1990; Mertens and
Milburn, 1992), the task of verifying that the ATCS
applicant possesses that ability becomes a primary pre-
employment concern.

Currently, the FAA accepts several clinical color
vision tests for use in testing ATCS applicants (see Table
1). Those tests were intended to identify individuals with
normal color vision. Mertens (1990) performed a study
to validate all FAA-accepted clinical color vision tests
using simulations of the four above-mentioned ATCS
tasks from ATC and FSS facilities tasks that involve non-
redundant color coding. Mertens studied 37 normal
trichromats and 71 individuals with red-green color
vision deficiency of varying type and degree. The validi-
ties of several tests were in the vicinity of 0.90 for
prediction of error-free performance in ATCS color
tasks, but several tests had undesirably high false alarm
rates.

The present research replicated part of Mertens’
(1990) study for the purpose of increasing the sample
size in all color vision diagnostic categories to provide
gtearer confidence in conclusions drawn from these
analyses of color vision test validity. Data from the earlier
and present studies were combined for the present analy-
SIS.

METHODS

Subjects.

The prior experiment by Mertens (1990; n=108),
and the present study (n=136) involved a total of 244
subjects, including 121 normal trichromats (normal
color vision), and 123 individuals with red-green color
vision deficiencies of varying magnitude and of both
protan (red weak) and deutan (green weak) types of
deficiencies. Complete information concerning age of
subjects and the distribution of males and females in each
study, and color vision classifications of subjects, is
presented in the report of a companion study (Mertens
and Milburn, 1992). The companion study involved the
same subjects and testing sessions, but was performed
both to expand the data base supporting color vision
requirements for ATCSs, and to more sharply define the
relationship between type and degree of cclor vision
deficiency and accurate performance of ATCS color
tasks.

All subjects had at least 20/30 visual acuity in both
near and distant vision, as measured by the Titmus
Vision Tester or the Bausch and Lomb Orthorater vision
tester. Subjects were recruited through advertisements in
newsletters at Tinker Air Force Base, area colleges and
universities, and through local newspapers of the Okla-
homa City (OK) metropolitan area. Al! subjects were
paid an hourly wage.

Diagnostic Color Vision Tests.

The procedure used for classification of deficien-
cies involved the Nagel Type I anomaloscope to classify
individuals with red-green color vision deficiency, and
other tests to detect and diagnose the rare blue-yellow
deficiencies that the Nagel anomaloscope does not de-
tect. None of the latter were found. A detailed descrip-


APPENDIX A

Table 1

Color Vision Tests Accepted by the FAA for Airmen Certification

ACCEPTED TESTS

Pse

udcisochromatic Plate Tests

- AOC (18-Plate)

2.
3.
4.

5.

6.
7.
8.
a

AOC (15-Plate)

Richmond

AOC-HRR

Ovorine (2nd Ed.)

Ishinara’s Tests for Color-Blindness
Ishihara (14-Plate)
Ishihara (16-Plate)
Ishihara (24-Plate)

. Ishihara (38-Plate)

Lantern Tests

10.
11.
12.

Edridge-Green Lantern
Farnsworth Lantern

SAMCTT

Multifunction Vision Testers

13.

14,
15.
16.

Keystone Orthcscope/
Telebinocular

OPTEC 2000
Titmus

‘Titmus II

FULL TEST NAME

American Optical Company Pseudoisochromatic
Plates - 1940 Edition.

American Optical Company Pseudoisochromatic
Plates - 1965 Edition

Richmond Pseudo-Isochromatic [sic] Plates for
Testing Color Perception

American Optical - Hardy, Rand, Rittler
Pseudoisochromatic Plates - Second Edition

Dvorine Pseudo-Isochromatic [sic] Plates -
Second Edition

Concise Edition

16 Plates Edition
24 Plates Edition
38 Plates Edition

Edridge-Green Colour Perception Lantern
Farnsworth Lantern

School of Aviation Medicine Color
Threshold Tester

Keystone Telebinocular Test Unit, Aeromedical
Modei

OPTEC 2000 Vision Tester, Aeromedical Modet
Titmus Vision Tester

Titrus i

ision Tester

A-1

ATCS FAILURE CR:TERIA
(Ciass | Certification)

4 of more arrors, slates 1-18
5 or more errors, plates 1-15
5 or more errors, plates 1-15
any error on platss 1-6

3 or more errors. plates 1-15

2 or more errors, plates 1-11
2 or more errors, plates 1-8
3 or more errors, plates 1-15

4 of more errors, plates 1-21

not studied, rarely used
avg. of more than 1 error per series

not studied, no longer used by USAF

any error

any error
any error

any error


of magnitude) was located 7 deg above the center of the
target. Each color segment in the bar subtended 0.5 deg
vertically and 1.3 deg horizontally. The radar task re-
quired identifying the color ofa0.5 deg square target that
was located at the center of a 4 deg square background.
All possible combinations of target/background colors
were used to discourage guessing, but only the 12 com-
binations most commonly found in radar, and which
represent adjacent precipitation levels, were used for test
trials and scored. There was no tims limit for responding.
Following a response, there was a 5-s delay before presen-
tation of the next stimulus. Any error caused failt:ze of
the test. Total errors were also counted.

Color Weather Radar Test-Small Targets (Radar-S).
This task was identical to Radar-L, with the exception
that targets were smaller, subtending approximately 0.1
deg. The 0.5 deg target size of Radar-L was chosen to be
sufficiently large so that color discrimination of indi-
viduals with normal color vision would not be adversely
affected by target size. With the 0.1 deg size, somewhat
decreased discrimination ability for colors on the red-
gteen axis was expected. Discussions with Flight Service
Specialists and meteorologists working at FAA facilities
indicated that identification of the color of very small
werther radar targets is important. The 0.1 deg target size
was similar to the size of small targets seen on several
weather radar displays at FSS and en route centers and is
approximately 4 x 4 pixels in size on the Tektronix 4125
color graphics work station used to present the weather
radar tasks. The monitor, 38.3 cm on the diagonal, had
a resolution of 1280 x 1024 pixels. Lahey, et al. (1984a)
also selected 0.1 deg as a small target size relevant to
ATCS color tasks.

Aeromedical Color Vision Screening Tests.

Ail aeromedical color vision screening tests currently
known to be in use by Aviation Medical Examiners
(AMEs) for the initial medical examinations of ATCSs
and pilots were evaluated. These tests can be grouped
into three categories: 1) nine pseudoisochromatic plate
tests, 2) three lantern tests, and 3) four multifunction
vision testers; they are listed in Table 1 with: their First
Class disposition criteria (FAA Aviation Medical
Examiner's Guide 1980). The Class I criteria are in-
tended to select normal trichromats.

Pseudoisochromatic Plate Tests. The 14-, 16-, and
24-plate Ishihara tests all involve subsets of plates from
the 38-plate Ishihara test. Only the 14-plate and 38-plate
ishihara tests were administered. Scores for the 16- and
24-plate tests were computed based on responses to
appropriate subsets of plates of the 38-plate test. It is
assumed that any differences between the plates of this
simulatiun and the actual plates of those tests are minor
and would be similar to different printings of the same
plate. The Dvorine, Richmond, and AOC-18 plate, -15
plate and -HRR were also given. The full test names are
given on Table 1. A Macbeth Easel Lamp was used to
illuminate all plate tests, with all other lighting extin-
guished during testing. All screening tests were adminis-
tered according to manufacturer's directions.

Lantern Tests. Tie Farnsworth Lantern test was
developed by the U.S. Navy and is currently used for
aeromedical screening by both the Navy and the U.S. Air
Force. The Farnsworth Lantern test was given in a
normally lighted room, according to the manufacturer's
directions, with the subject positioned 8 ft in frontof the
lantern. The U.S. Air Force's School of Aviation Medi-
cine Color Threshold Tester (SAM-CTT) was given, but
those data are not included in this report since use of the
SAM-CTT by the U.S. Air Force has recently been
discontinued. The Edridge-Green Lantern test was not
given because its use is rare and there are no known
standard procedures for test administration.

Multifunction Vision Testers. Several multifunction
vision instruments include color vision tests that are
accepted by the FAA; all involve photographic reproduc-
tions, cither prints or positive transparencies, of
pseudoisochromatic plates. The Titmus, Titmus II, and
OPTEC 2000 vision testers all involve positive color
transparencies, which are reproductions of Ishihara test
plates, Each of these tests was given in a different testing
room at a different time and in a dimly-lit room. The
Keystone test involves photographs of six plates, which
were developed specifically for that test. The Keystone
test was illuminated using only that instrument's lamp;
room lights were turned off.

Procedure.

The simulated ATCS color tasks, diagnostic tests,
and clinical color vision tests were administered at four
testing stations, each supervised by a trained laboratory


tion of diagnostic methods is found in Mertens and
Milburn (1992),

ATCS Color Tasks Serving as Validation
Criteria.

Flight Progress Strip (FPS) Test. The FPS test was
similar to tests used in previous research by Adams and
Tague (1985), It required idencification of colors in
color-coded computer printing or handwriting on FPSs
as used at en route centers. Subjects responded by
verbally identifying the color of computer printing (103
items) and handwriting (76 items) as red or black (blue).
Since blue may be used instead of black, a small number
of blue items were included. FPS materials were obtained
from Ft. Worth, Texas; en route center and representa-
tive samples were selected. There was no time limit for
responding and performance was assessed in terms of
number of errors and pass-fail; the failure criterion was
any error. The incident illumination level was 59 lux, an
average workstation illumination measured at the Ft.
Worth en route center.

Flight Progress Strip Test-Low Illumination (FPS-L)
and -Normal Illumination (FPS-N). These tests compare
the effects of low illumination with normal illumination.
A subset of 38 of the hand-written items from the above
FPS test were presented a second time under a lower, 14
lux incident illumination level. In subsequent discus-
sion, data that concern testing with this subset of FPS test
items at the normal 59 lux illumination level are referred
to as the FPS-N test. The low illumination level for the
FPS-L test was selected to be marginal for normals based
on prefiminary measurements, but was slightly higher
than the lowest level (8.4 lux) found at an en route center
and reported by Adams and Tague (1985). There was no
time limit for responding, and performance was assessed
in terms of total errors and pass-fail; the failure criterion
was any error.

Aircraft Lights Test (ALT). Ten pairs of lights
simulating aircraft navigation lights were projected onto
a white screen positioned at eye level in a nearly dark
room. The subject was seated at a viewing distance of 20
ft from the target. The ambient illumination of the
screen was 1.07 lux, the recommended max:mum level
for interior incident illumination of tower cab windows
(Illumination Engineering Society, 1972). Kodak
Wratten Filters 26 and 58 were mounted over small

holes in slides to simulate red and green airccaft naviga-
tion lights. White navigation lights were simulated by
using no filter. Intensity of the lights was varied with
neutral density Wratten filters to ensure that color could
not be associated with brightness. Colors of simulated
aircraft lights had the following approximate CIE 1931
chromaticity coordinates: red, x=.693, y=.307; green,
x=.269, y=.683; and white, x=.460, y=.417. Although
this task was similar to the aircraft lights test of Adams
and Tague (1985) in terms of target colors, the angular
subtense of simulated aircraft light was smaller, 1.4 min
arc, and the two lights of each pair were separated
vertically by 21 min of arc. The target colors met current
standards of the International Civil Aviation Organiza-
tion (1988) for aircraft navigation light colors. The
ctiterion for failure of this test was any error.

Aviation Signal Light (ASL) Test, The subject identi-
fied signal colors as reflected in the indicator (bezel) on
top of an ASL. Six signals were observed as the subject
sighted the ASL out ofa third-floor, north window at the
sky, The signals were regulated by an experimenter with
controls shielded from the subject's view. Signals were of
5-s duration, and intervals between signals were 3 min.
The ASL signal colors (red, green, and white) were
presented randomly, with the restriction that each color
was presented at least once during the six trials. This test
was administered between the hours of 10:00 am and
3:00 pm with sky conditions varying from clear to
heavily overcast. Any error constituted failure of the task.

Color Weather Radar Test- Large Targets (Radar-L).
This test involved identifying seven colors, including the
six colors of the FAA weather radar color code, which
represent six different levels of precipitation, and black,
fepresenting no precipitation. The weather radar color
code involves two shades each of red, yellow, and green.
The characteristics of display colors, 1931 CIE chroma-
ticity coordinates x, y, and luminance (L=candelas per
Square meter) are presented in the companion paper
{Mercens and Milburn, 1992). The display color mea-
surements were made with the same ambient illumina-
tion (118 lux) that was present during testing. The
display colors and the 118 luxambient illumination level
were similar to measurements obtained at the FSS in
McAlester, Oklahoma. The display was viewed by the
subject at a distance of 71 cm. On each trial, a bar
showing the colors of all six precipitation levels (in order


The high validities of some clinical tests for pre-
dicting performance in the FPS and ALT tasks indicate
the requirement for a high level of color vision ability in
normal performance of those tasks. Almost all FAA-
accepted clinical color vision tests for the Class I standard
have low miss rates for the FPS and ALT tasks (see Tables
2, 4, and 6), but false alarm rates vary widely. An
anomaloscope diagnosis of normal trichrumat, or a
passing score on any one of several FAA-accepted color
vision plate tests designed to select normal trichromats,
were the best predictors of error-free performance on
simulated ATCS color tasks.

CONCLUSIONS

Accurate color vision is essential for performance of
certain critical Ai CS tasks. The collective data from
both the original and the replication studies show that
occurrence of error on simulated ATCS coler tasks was
rare among persons passing the recommended color
vision screening tests, and common among persons
failing those tests. The validities of the best clinical color
vision tests for prediction of performance on the Flight
Progress Strips, Aircraft Lights tasks, and composite
scores, are very high, in the vicinity of 0.90 or above.
Those validity levels are comparable to the validity of the
same clinical tests when used for differentiating between
normal trichromats and color vision deficients, as re-
ported by the NAS-NRC Committee on Vision (1981).

REFERENCES

Adams AJ, Tague MK. Performance of Air Traffic Control
Tasks by Protanopic Color Defectives. Am. J. Opt.
Physiol. Opt. 1985; 62:744-50.

Illumination Engineering Society. Illumination Engineer-
ing Handbook (Sth Ed.). New York: Illumination
Engineering Society of New York, 1972.

International Civil Aviation Organization. Airworthiness
technical manual. Document 9051-AN/896, Amend-
ment 10, 1000 Sherbrooke Street West, Suite 400,
Montreal, Quebec, Canada, Novenber 14, 1988.

Kuyk TK, Veres III JG, Lahey MA, Clark Dj. The ability of
protan coior defectives to perform color-dependent
air uraffc control tasks. Amer. J. Optom. Physiol.
Optics. 1986; 63:682-6.

Kuyk TK, Veres III IG, Lahey MA, and Clark DJ. Ability of
deutan color defectives to perform: simulated air traf-
fic control tasks. Amer. J. Optom. Physiol. Optics.
1987; 64:2-16.

Lahey MA, Veres III JG, Kuyk TK. Clark DJ, Smith EN.
Job Analysis and Determination of Color Vision
Requirements for Air Traffic Control Specialists. Re-
port submitted under Contract OPM-50-83 with the
U.S. Office of Personnel Management. 1984 (a)

Lahey MA, Kuyk TK, Veres lil JG, Clark DJ. The Impact
of Color Weather Radar Equipment on the Job of Air
Traffic Control Specialists - Flight Service Station
Option. Report submitted under Contract OPM-
50-83 with the U.S. Office of Personnel Manage-
ment. 1984 (b)

Mertens, H.W. Evaluation of Functional Color Vision
Requirements and Current Color Vision Screening
‘Tests for Air Traffic Control Specialists. Report DOT/
FAA/AM-90/9. Washington, DC: Federal Aviation
Administration, Office of Aviation Medicine, 1990.

Mertens, H.W. and Milburn, N.J. Performance of Color-
dependent Tasks of Air Traffic Control Specialists as
a Function of Type and Degree of Color Vision
Deficiency. Report DOT/EAA/AM-92/28. Wash-
ington, DC: Federal Aviation Administration, Office
of Aviation Medicine, 1992.

Nationa! Research Council-National Academy of Sciences,
Committee on Vision. Procedures for testing colo:
vision: Report of working group 41. Washington,
DC: National Academy Press, 1981.

Steen JA, Collins WE, Lewis MF. Utility of several clinical
tests of color defective vision in predicting daytime
and nighttime performance with the aviation signal
light gun. Aerospace Med. 1974; 45:467-472.


DOT/FAA/AM-92/29

Office of Aviation Medicine
Washington, D.C. 20591

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Validity of Clinical Color
Vision Tests for Air Traffic
Control Specialists

Henry W. Mertens
Nelda J. Milburn

Civil Aeromedical Institute
Federal Aviation Administration
Oklahoma City, Oklahoma 73125

October 1992

Final Report

:

This document is available to the public
through the National Technical Information

EE Springfield, Virginia 22161.
33 av od

CEE

geil

U.S. Department
of Transportation
Federal Aviation
Administration

92 11 28 064



Table 4

Validity of Aeromedical Color Vision Screening Tests for Prediction
of Performance on the FPS Test (59 lux tnumination)

ERROR RATE (%)

False Validity
TEST Miss Aijarm (Kappa)
Anomaioscope (Pass Normal or Mild) 0.9 10.4 88
FAA-Accepted Tests (Class 1)
AOC (15-Plate} 0.9 15.7 82
Richmond 0.9 12.7 85
AOC (18-Plate) 2.7 20.1 -76
AOC-RR 0.9 11.9 86
Ishihara (14-Plate) 0.9 Q.7 -89
Ishihara (16-Plate) 0.9 40.4 88
Ishihara (24-Plate) 0.9 8.2 -90
Ishihara (38-Plate) 0.9 8.2 -90
Dvorine 0.9 10.4 88
Titmus Tester 0.9 56.0 41
Titmus i Tester 0.9 51.5 45
OPTEC 2000 1.8 33.6 -62
iweystone 0.9 14.2 -84
Farnsworth Lantern 8.3 6.0 -86

Table 5

Validity of Color Vision Selection Tests for Prediction of
Performance on the Flight Progress Strips Subtest Given
Under Both Normal (FPS-N) and Low {FPS-L} Illumination

NORMAL ILLUM. (59 tux) LOW ILLUM. (14 Lux)
Error Rate (%i Error Rate {%)
False Validity False Validity
TEST Miss Alarm (Kappa) Miss Alarm (Kappa)
Anomaioscope (Pass Normal 0.0 13.6 -84 3.5 9.3 .87
or Mild)
FAA-Accepted Tests (Class |)
AOC (15-Plate) 0.0 8 18.6 79 2.6 14.0 .83
Richmond 0.0 15.7 -82 1.7 10.1 88
AQC (18-Plate) 1.9 22.9 .73 4.3 18.6 76
ACC-HRR 0.0 15.0 -83 2.6 10.1 .87
Ishihara (14-Plate) 0.0 12.9 85 3.5 8.5 88
Ishihara (16-Plate) 0.0 13.6 84 2.6 8.5 89
Ishihara (24-Plate) 0.0 11.4 87 3.5 7.0 8S
Ishihara (38-Plate) 0.0 11.4 87 3.5 7.0 89
Dvorine 0.0 13.6 84 3.5 3.3 87
Titmus Tester 0.0 57.1 39 0.9 54.3 43
Titmus Hl Tester 0.0 52.9 43 0.S 43.6 48
OPTEC 2000 1.0 35.7 -60 1.7 31.0 -66
Keystone 0.0 17.4 80 2.6 12.4 84
Farnsworth Lantern 6.8 8.6 84 10.5 47 85

A-3


Table 2

Validity of Color Vision Selection Tests for Prediction of
Composite Scores on Three ATC Tasks
(FPS, ASL, and ALT)

ERROR RATE (%
False
TEST Miss Alarm
Anomaloscope (Pass Normal or Mild) 1.7 5.6 83

FAA-Accepted Tests (Class |)

AOC (15-Plate) 7 W144 -87
Richmond 1.7 7.9 90
AOC (18-Plate) 2.5 15.1 -82
AOC-HRR 17 7A 91
Ishihara (14-Plate} 1.7 4.8 -93
Ishihara (16-Plate) 1.7 5.6 -93
Ishihara {24-Plate) 1.7 3.2 95
ishihara (38-Plate} 1.7 3.2 .95
Dvorine 1.7 5.6 -93
Titmus Tester 1.7 54.0 44
Titmus J} Tester 0.8 48.4 -50
OPTEC 2000 2.5 30.2 67
Keystone 1.7 9.5 -89
Farnsworth Lantern 9.4 1.6 .89
Table 3
Validity of Color Vision Selection Tests for Prediction of Overall
ATC/FSS Task Performance (Fail on Any Task Under Normal Conditions)
ERROR RATE (%
False Validity
TEST Miss Alarm {Kappa)
Anomaloscope (Pass Normal or Mild) 6.4 5.0 89
FAA-Accepted Tests (Class 1)
AOQC {15-Plate) 5.6 10.4 84
Richmond 6.4 76 86
AQC (18-Plate} 5.6 13.4 81
AOC-HRR 6.4 6.7 -87
Ishihara (14-Plate) 6.4 4.2 83
Ishihara (16-Plate} 6.4 5.0 89
Ishihara (24-Plate) 6.4 2.5 91
ishihara (38-Plate) 6.4 2.5 91
Dvorine 6.4 5.0 89
Titmus Tester 3.2 52.9 44
Titmus {! Tester 2.4 47.4 51
OPTEC 2000 6.4 30.3 64
Keystone 6.4 9.2 84
Farnsworth Lantern 13.7 0.8 85

A-2


technician. All anomaloscope testing was performed by
the senior researcher. The tests at cach station took
approximately 45 min to administer. The testing ofeach
subject was performed in two, 2-hour sessions separated
by a 1-hour lunch break or given on successive days.
Within each session, the two 45-min testing periods
were separated by a 15-min break. Since the OPTEC
2000, Titmus, and Titmus II involved reproductions of
the same set of six Ishihara plates, each of those tests was
placed at a different testing station to separate them in
time and by administrations of several other tests.

RESULTS AND DISCUSSION

Relation of ATCS Color Task Performance to
Clinical Color Vision Tests.

The validities of color vision tests currently in use
for aeromedical screening of ATCS personnel were evalu-
ated regarding prediction of pass/fail performance on the
ATCS color tasks. The validity of screening tests was also
compared with the validity of anomaloscope classifica-
tion as a predictor of performance. Cohen's (1960)
Kappa (K), an index of agreement, was used to assess the
validity of the color vision screening tests, as recom-
mended by the NAS-NRC Committee on Vision (1981).
The index can be interpreted as the precentage agree-
ment between test and criterion variable, with correction
forchance. The four ATCS color tasks involving normal
and difficult color task situations were used as the criteria
for assessing the screening tests. That is, the four ATCS
color tasks were used as samples of critical ATCS work
behaviors against which the color vision tests were vali-
dated as personnel selection criteria. These data on
validity are given in Tables 3, 4, 5, 6, 7, and 8. Validities
given in Table 2 involve a composite pass/fail score for
the three ATC rasks, the FPS, ALT, and ASL tasks; this
overall score is named the ATC Tasks score. Validities
given in Table 3 involve an overall composite score for
the same three ATC tasks plus the FSS-related Radar-L
task; this overall score is named the ATC/FSS Tasks
score. Both composite scores involved only normal con-
ditions and did not involve the low illumination condi-
tion of the FPS-L task or the small radar target size of the
Radar-S task. Failure of any test among the three ATC
tasks performed under normal conditions caused failure
on the ATC Tasks score. Failure of any test among those

three ATC tasks, or the Radar-L task, caused failure on
the ATC/FSS Tasks score. In addition to those simula-
tions, which represent common conditions in tasks,
validities are also given for prediction of performance in
the FPS task under low illumination (FPS-L) and in the
Radar task with smaller target sizes (Radar-S). The latter
are less common conditions, but still within the range of
conditions that could occur in those tasks. In addition to
validities, each tabie lists the miss and false alarm rate for
each test. Miss rate is the probability of passing the
clinical test, given failure on the criterion ATC or FSS
color task. The false alarm rate is the probability of failing
the screening test, given passing on the criterion task.
Miss and false alarm rates are sometimes alternatively
referred to as false negative rate and false positive rate,
tespectively.

A diagnosis of normal trichromat, as defined in
Mertens and Milburn (1992), was required for "passing"
theanomaloscope test in the present analysis. Passing the
anomaloscope was highly related to performance on the
ATC Tasks score (K=.93), the ATC/FSS Tasks score
(K=.89), the FPS Task (K=.88), and the ALT (K+.88), as
shown in Tables 2, 3, 4, and 6. Several color vision plate
tests had comparably high validities in predicting those
scores. The plate tests with high validity were those
known to have high validity for screening normal trichro-
mats. The validities of the anomaloscope test were lower
in prediction of performance on the Radar-L and ASL
task (see Tables 7 and 8), primarily due to higher false
positive rates, As shown by Mertensand Milburn (1992),
more simple and extreme anomalous trichromats were
able to pass those tasks than the other ATCS tasks
studied. The highest validity obtained for prediction of
performance on the Radar-L (K=.81) and ASL (K=.76)
tasks was with the Farnsworth Lantern. That test is
known to pass some individuals diagnosed as simple
anomalous by the anomaloscope (Steen, et al., 1974).
The FPS-L and Radar-S simulated observation condi-
tions were more difficult, as expected, than the corre-
spcading FPS-N and Radas-L tasks (see Tables 5 and 8,
respectively). The greater difficulty in the FPS-L and
Radar-S tasks was reflected by a decrease in the false
alarm rate and an increase in the miss rate for all clinica!
tests, compared to corresponding rates when perfor-
mance on FPS-N and Radar-L tasks were predicted.


ACKNOWLEDGEMENTS

The authors wish to acknowledge the contributions of Linda Matthews, Clara Williams,
Sandra Miller, LaDonna Moore, Cynthia Fox, Jody Worley, and Chan Hellman who assisted
in organization of testing, data collection and data analysis. Patsy Fowler assisted in assembly of
testing materials. Many volunteers were obtained from military and civilian personnel working
at Tinker Air Force Base due to the support and assistance of the offices of the Base Commander
and Tinker Hospital in soliciting volunteers; we particularly thank Lt. Col. Richard Baldwin and
Le. Col. Roger Miller for their help.

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Technical Report Documentation Page

T. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
DOT/FAA/AM-92/29 |

“4. Title ond Subtitle 5. Report Date

Validity of Clinical Color Vision Tests for Air October 1992
Traffic Control Specialists . 6. Performing Orgonizotion Code

8. Performing Organizetion Report No.

7. Author!s)

Henry W. Mertens, Ph.D. and Nelda J. Milburn, M.Ed.
9, Pertorming Organization Name end Address 10. Work Unit No. (TRAIS)

FAA Civil Aeromedical Institute
P.O. Box 25082 VW. Contract or Grant No.
Oklahoma City, OK 73125

T3. Type of Report ond Period Covered

12. Sponsoring Agency Name and Address
Office of Aviation Medicine
Federal Aviation Administration
800 Independence Ave., S.W. 14. Sponsoring Agency Code
Washington, D.C. 20591

15. Supplementary Notes

This work was performed under task AM-C-88-90-HRR-107

16, Abstrect

An experiment on the relationship between aeromedical color vision screening test
performance and performance on color-dependent tasks of Air Traffic Control
Specialists was replicated to expand the data base supporting the job-related
validity of the screening tests. The original experiment (Mertens, 1990; n=108),
and the replication (n=136) involved a tetal of 121 normal trichromets, 31 simple
and 44 extreme anamalous trichromats, and 48 dichromats; both protans and deutans
were included. The simulations of ATCS color tasks which served as validation
criteria were flight progress strips (en route centers), aircraft lights and the
Aviation Signal Light indicator (ATC terminal operations), and color weather radar
(flight service station and en route center facilities). The validities (Kappa)
of aeromedical screening tests ranged from 0.44 to 0.91 for prediction of error-—
free performance on all color dependent tasks. The aeromedical screening tests
were generally acceptable in terms of selecting individuals who did not sake errors,
but several tests had high false alarm rates. The high job-related validity of
several aeromedical color vision tests was cenfirmed.

VW. Key Words 18, Distribution Statement

Air Traffic Controllers Document is available to the public

Color Vision Standards through the National Technical

Performance Tests Information Service, Springfield,

Color Vision Tests Virginia 22161

19. Security Classif. (of this report) DD. Security Clossif. (of this page) 21. No. of Pages | 22. Price
Unclassified Unclassified 14

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


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 or use thereof.



Table 6

Vatidity of Color Vision Selection Tests for Prediction of
Performance on the Aircraft Lights Test

ERROR RATE

False Validity

TEST Miss Alarm iKappa)
Anomaloscape (Pass Normat or Miid) 1.8 £.8 .88

FAA-Accepted Tests (Class I)
AOC (15-Plate) 1.8 15.2 -82
Richmond 1.8 12.1 85
AOC (18-Plate) 2.7 18.9 77
AOC-HRR 1.8 11.4 -86
Ishihara (14-Plate’ 1.8 9.1 83
ishihura (16-Plate} 1.8 9.8 88
Ishihara (24-Plate) 1.8 7.6 -90
Ishihara (38-Piate) 1.8 7.6 -80
Dvorine 1.8 3.8 -88
Titmus Tester 1.8 56.1 -40
Titmus I! Tester 0.9 50.8 -46
OPTEC 2000 2.7 33.3 -62
Keystone 1.8 13.6 -84
Farnsworth Lantern 8.9 4.6 -87
Table 7
Validity of Color Vision Selection Tests for Prediction of
Perfarmance on the Aviation Signal Light Indicator Test
ERROR RATE (%)

False Validity

TEST Miss Alarm (Kaopa)
Anomaloscope (Pass Normal or Miid) 0.0 24.1 69

FAA-Accepted Tests (Class |)

AOC {15-Plate) 0.0 28.5 64
Richmond 0.0 25.2 66
AOC (18-Plate) 4.2 31.6 59
AOC-HRR 0.0 25.3 -67
Ishihara (14-Plate) 0.0 23.4 -6E
Ishihara {16-Plate) 0.0 24.1 69
ishihara (24-Plate} 0.0 22.2 71
tshihara (38-Plate) 0.0 22.2 71
Dvorine 0.0 23.4 .69
Titmus Tester 0.0 62.0 -30
Titmus {I Tester 0.0 58.2 33
OPTEC 2000 1.2 43.6 AT
Keystone 0.0 27.2 65
Farnsworth Lantern 2.4 16.5 76

A4