a)
a
a
_———e)
i
HH
_——)
_
a
—————
———_
> —s
—
-—————_4
——i
eH
—
=
—
H
H
H
eI

Extreme Deuteranomalous

Ju

Deuteranopic

Severe Deuteranomalous

Moderate Deuteranomalous

a Mild Deuteranomalous
- Borderline Defective - Deuteranomalous

Normal
= Mild Protanomalous

Severe Protanomalous
or Protanopic

Extreme Protanomalous

A BUN OOONAADUN = OOBNOGAUN—OOOVOGAUN-OOBIAADUN—OOBVOUDUN —
J

A OF BOGGddDD DED DS AUUGUY UUOONNRONMUNNN=—~-—-~--—

Ficure 1. Range of anomaloscope matches made by subjects under conditions of “neutral” adaptation (solid
lines) and, where different, chromatic adaptation (broken lines).

ment in test results of performance in day and
night testing should be considered as conditional.
The day testing was completed first in all cases,
and the effect of the previous practice on the
results of the night testing is unknown. With a
larger test population and an alternative test
procedure, the results might have been very
different.

Contingency tables showing the efficiency of
each clinical test in predicting day and night
performance on the signal light gun test are
shown in the Appendix. The results are sum-
marized in Table 1. The phi coefficient shows
how well each test fared as a predictor of per-
formance on the practical test. As can be seen
from a comparison of the phi coefficients, cor-

relations on all tests dropped under the nighttime
condition with the exception of the Dvorine
plates. In two cases, the correlations fell below
an acceptable level of significance. In general,
the efficiency of the clinical tests to predict per-
formance on the practical test when given at
night was less than satisfactory.

There was also a trend toward lower “miss”
rates, that is, the percentage of the subjects that
passed the clinical test but failed the practical
test. This is important as the “miss” rate repre-
sents those applicants who will receive certificates
with no color vision restrictions, but who should
be issued a certificate with the color vision
restriction.

Both the lower “miss” rate and the lower phi



DAY
SIGNAL GUN TEST

P F
F| 145 491
SAMCTT
P 29! O73
436 564
@ = .55*

636

.364

SAMCTT

55

* Correlations are singnificant at the .O! level.
** Correlations are singnificant at the .05 level.

NIGHT
SIGNAL GUN TEST
P F
327 309 | .636
309 .055 | .364
636 364
@ = .33**

Fieure 3. Contingency tables showing the per cent of subjects who passed and failed the signal light gun test

under day and night conditions and who passed and failed the Color Threshold Tester.

and night conditions are also shown.

F

DVORINE

P

DAY
SIGNAL GUN TEST
P F
.218 .509
218 .055
436 564
@ =.45*

-727

-273

55

DVORINE

* Correlations are significant at the .O! level.

P

Phi coefficients for day

NIGHT
SIGNAL GUN TEST
P F
364 .364 | .728
273 .000 | .273
637 364
@ = .46*

Fieure 4, Contingency tables showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions and who passed and failed the Dvorine plates. Phi coefficients for day and
night conditions are also shown.


e

i

. Lewis,

REFERENCES

. Federal Aviation Administration: Guide for Aviation

Medical Examiners. Department of Transportation,
Federal Aviation Administration, Office of Aviation
Medicine, June 1970.

M. KF, and J. A. Steen: Colour Defective
Vision and the Recognition of Aviation Colour Signal
Light Flashes, PROCEEDINGS OF THE INTERNA-
TIONAL SYMPOSIUM ON THE PERCEPTION AND
APPLICATION OF FLASHING LIGHTS, London,
In Press.

. Hardy, L. H., G. Rand, and M. ©. Rittler: The H-R-R

Polychromatic Plates. I. A Test for the Detection,
Classification, and Estimation of the Degree of De-
fective Color Vision, A.M.A, ARCH. OPHTHAL., 51:
216-228, 1954.

. Hardy, L. H., G. Rand, and M. ©. Rittler: The H-R-R

Polychromatic Plates. II. Comparison of Qualita-

Pa

a

mv

tive and Quantitative Classifications by H-R-R Plates
and Other Tests, A.M.A. ARCH. OPHTHAL., 52:
353-368, 1954.

. Farnsworth, D,: The Farnsworth-Munsell 100-Hue

and Dichotomous Tests for Color Vision, J. OPT.
SOC. AMER., 38:568-578, 1943.

Rowland, L. S.: Selection and Validation of Tests
for Color Vision—Ielationship between Degree of
Color Deficiency and Ability to Identify Signals from
a “Biscuit Gun.” School of Aviation Medicine;
Project Report No. 137-7, November 1953.
Farnsworth, D., and P., Foreman: Development and
‘Trial of the New London Navy Lantern as a Selection
Test for Serviceable Color Vision, BuMed Project
X-457 (AV-241-K), Color Vision Report No, 12,
U.S. Submarine Base, New London, Connefticut,
6 May 1946,



Table 1

Correlation between clinical tests and

the color signal light gun test.

Day Night

Phi Per Cent Phi Per Cent
Test Coefficient "Misses" Coefficient ‘Misses’
A.O. HeR-R 252% 7.3 023 7.3
Anomaloscope 50% id) 233% 1)
Color Threshold Tester .55* 7.3 2 33%% 5.5
Dvorine Plates 45* 5.5 46% 0
Farnsworth Lantern 44% 1.8 236% 0
Farnsworth 100-Hue 45% 5.5 21 5.5
Farnsworth Panel D-15 .55* 9.1 46% 3.6

* Correlations are significant at the .01 level.
** Correlations are significant at the .05 level.

coefficients may be attributed to an increase in
the false alarm rate. The false alarm rate is
that percentage of subjects that failed the clinical
test but passed the practical test. As can be seen
in Table 2, the false alarm rate for all tests in-
creased under nighttime conditions. This points
out the need for applicants who fail the clinical
test to be allowed to take a practical test, given

Table 2
False alarm rate between clinical tests

Test

A.O, H-R-R
Anomaloscope

Color Threshold Tester
Dvorine Plates
Farnsworth Lantern
Farnsworth 100-Hue

Farnsworth Panel D-15

under the conditions in which his license would
then be valid.

The lower correlations and the higher false
alarm rates of the clinical tests when compared
with a practical test given at night indicate the
need for an inexpensive, less time-consuming,
more efficient test for predicting color vision
abilities at night.

and the color signal light gun test.

Day Night
16.4 36.4
27.3 47.3
14.5 32.7
21.8 36.4
27.3 45.5
21.8 41.8
12.7 27.3



APPENDIX

DAY NIGHT
SIGNAL GUN TEST SIGNAL GUN TEST

P F P F

F| 164 491 | .655 F | .364 291 | 655
H-R-R H-R-R

P| .273 073 | .346 P| .273 073 | .346

.437 564 637 264

@ = .52* @ = .23
N= 55

* Correlations are significant at the .OI level.

Fieure 1, Contingency tables showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions and who passed and failed the A. O. H-R-R plates. Phi coefficients for day and
night conditions are also shown,

DAY NIGHT
SIGNAL GUN TEST SIGNAL GUN TEST
Pp F P F
Fl .273 564 837 F 473 364 | .837
ANOMALOSCOPE ANOMALOSCOPE
Pl 164 .000 | .164 Pj 1164 000 164
437 564 637 1364
@ = .50* @ = .33**
N=55

* Correlations are significant at the .O! level.
** Correlations are significant at the .O5 level.

Fieure 2. Contingency tables showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions and who passed and failed the anomaloscope. Phi coefficients for day and night
conditions are also shown.



TECHNICAL REPORT STANDARD TITLE PAGE

T. Report No. 2. Government Accession No. 3. Recipient's Catalog No.
FAA-AM-71-32
4. Title and Subtitle 5. Report Date

July 1971

COLOR DEFECTIVE VISION AND DAY AND NIGHT RECOGNITION [%. Performing Organization Code
OF AVIATION COLOR SIGNAL LIGHT FLASHES

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

Jo Ann Steen, B.A.
Mark F. Lewis, Ph.D.

9. Performing Orgonization Name and Address 10. Work Unit No.

FAA Civil Aeromedical Institute
P. 0. Box 25082 TT. Controct or Grant No.
Oklahoma City, Oklahoma 73125

3. Type of Report and Period Covered

12. Sponsoring Agency Name and Address

Office of Aviation Medicine OAM Report
Federal Aviation Administration
800 Independence Ave., S.W. 14. Sponsoring Agency Code

Washington, D. C. 20590

15. Supplementary Notes

This research was conducted under
Tasks No, AM-B-69-PSY-19, AM-A-70-PSY-19, and AM-A-71-PSY-19,

16. Abstract
In a previous study, we reported the efficiency with which various tests of color
defective vision predict performance during daylight conditions on a practical
test of ability to discriminate aviation signal red, white, and green. In the
current study, subgroups of the subjects used in the previous investigation were
tested with the signal light gun at night.

Comparisons of the efficiency of each of seven tests of color defective vision in
predicting performance under day and night conditions are reported. In general,

the commercial tests were less efficient in predicting performance at night than

in the daytime. This reduction in efficiency may be attributed to an increase in
the false alarm rate of each test.

17, Key Words 18. Distribution Statement
Availability is unlimited. Document may
Color Vision be released to the National Technical
Signal Lights Information Service, Springfield, Virginia
Night Flight 22151, for sale to the public.

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

Unpublished Unpublished ai $3.00
Form DOT F 1700.7 (s-69)



DAY NIGHT

SIGNAL GUN TEST SIGNAL GUN TEST

P F Pp F

Fi} 127 .473 | .600 F | .273 .327 | .600
D-15 D-1I5

P} .309 091 .400 P| .364 .036 | .400

436 564 637 363

@ = .55* @ = .46*

N=55

* Correlation are significant at the .O! level.

Ficure 7. Contingency tables showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions and who passed and failed the Farnsworth Panel D-15 test. Phi coefficients
for day and night conditions are also shown.

10


DAY NIGHT

SIGNAL GUN TEST SIGNAL GUN TEST

P F P F

F 273 545 | 818 F | .455 364 | 819
FARNSWORTH FARNSWORTH
LANTERN LANTERN

P| 164 .018 182 P| .182 .000 | .182

437 563 637 1364

@=.44* ® = .36*

N=55

* Correlations are significant at the .Ol level.

Fiavre 5. Contingency tables showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions and who passed and failed the Farnsworth Lantern test. Phi coefficients for
day and night conditions are also shown.

DAY NIGHT
SIGNAL GUN TEST SIGNAL GUN TEST
P F P F
F .218 -509 727 F 418 .309 727
100 - HUE 100- HUE
Pp .218 .055 .273 P 218 055 .273
-436 564 636 .364
® = .45* @ =.2!
N=55

* Correlations are significant to the .OI level.

Ficure 6. Contingency tables showing the per cent of subjects who passed and fafled the signal light gun test
under day and night conditions and who passed and failed the Farnsworth 100-hue test. Phi coefficients for
day and night conditions are also shown.





nance of the test light and the lower has color
filters to vary color. The test, given in a dark-
ened room, consisted of showing and naming
the eight colors at the highest luminance and
then having the subject name them at the low-
est luminance first, then at each succeedingly
higher luminance. The order of presentation
was reversed from each previous showing.
Failure was considered to be a score of 49
or less,

6. The Farnsworth Lantern, developed by
the Navy,’ has a pair of vertically arrayed
lights. They can be red, green, or white in
any combination, and all nine possible pairs
were shown to the subject in a random order.
The test was given in a lighted room. The
subject pased if he completed the first run of
the nine color pairs with no errors. If an
error was made, two more runs were shown
and scored and a failure was an average of
more than one error per run for the last two
runs.

7. The Nagel-type anomaloscope displays a
monocular illuminated view of a bipartite
circle. The top half is a variable red-green
mixture, and the bottom is a yellow whose
luminance can be varied. The subject was
first told to stare at the Trendelenburg adapta-
tion light for two minutes. Then he was asked
to look into the anomaloscope at the circle and
to vary both halves until they matched exactly
in color and in brightness. He was then asked
to match a color set by the examiner in the
top half of the circle by varying the luminance
of the bottom portion. Between each match,
he was told to stare at the adaptation light for
30 seconds. The procedure continued until the
outside limits for each subject’s matches were
reached. After the series under “neutral”
adaptation, a chromatic adaptation series was
run. The subject was asked to continue star-
ing into the anomaloscope at the circle between
his matches and to adjust the luminance as the
examiner adjusted the red-green mixture.
Ranges for both series were noted and those
outside a range from 88 to 44 on a scale for
the red-green mixture of 0 to 73 were consid-
ered defective. This pass-fail criterion and
also the classifications for mild, moderate, and
severe deficiencies were arbitrarily selected for
purposes of comparison with other tests. A
range of 10 or less was classified as a mild

defect, 11 to 25 as a moderate one, and 26 or

more as a severe defect. An anomaly was

diagnosed when the range under chromatic
adaptation was greater than the range under

“neutral” adaptation.

8. The signal light gun test was given to
each subject during the day. The gun was
stationed indoors at an elevation of 38 feet.
The subject was tested outdoors at distances
of 1000 and 1500 feet from the window and
asked to identify a five-second flash of aviation
signal red, green, or white. Three flashes were
presented two minutes apart at each distance.
The order of presentation was selected ran-
domly but each color was presented at least
once in each six-flash series. The subject was
asked to identify the color before the termina-
tion of the flash. The failure criterion was
any error.

The eight preceding tests were given to the
subjects in the previous studies. In this investi-
gation, the subjects were each tested with the
color signal light gun at night using a procedure
identical to that used in the daylight testing.

IIL. Results and Discussion.

The color vision deficiencies of the subject
population, as diagnosed by the anomaloscope
test, are seen in Figure 1. The ranges obtained
under chromatic adaptation from subjects labeled
extreme anomalies are indicated by broken lines,
while solid lines indicate the matches obtained
under “neutral” adaptation. The degree of
severity of the defects can be seen as well as the
distribution of the types of color deficiencies.

These subjects were given the signal light gun
test under both day and night conditions. Of
the 55 subjects, 20 of those that passed the day
test also passed the night test. In terms of the
number of flashes missed on the signal light gun
test, of the 35 that failed the practical test under
day or night or both conditions, 28 subjects made
fewer mistakes at night, six made more mistakes,
and one subject remained the same. When the
subjects were broken down into the two main
types of color deficiency, protan and deutan,
there was no significant difference in the rates
of improvement; i.e., 17% more protans and 23%
more deutans passed the signal light gun test
when given at night. However, any improve-


COLOR DEFECTIVE VISION AND DAY AND NIGHT RECOGNITION
OF AVIATION COLOR SIGNAL LIGHT FLASHES

I. Introduction.

Candidates for Federal Aviation Administra-
tion medical certificates (Class II and IIT) must
be able to discriminate aviation signal red, green,
and white. Currently, a number of clinical tests
are being used by Aviation Medical Examiners
to satisfy this color vision requirement. In a
previous study,? subjects were given several of
these clinical tests together with a practical test
of their color vision abilities. This practical test,
using the signal light gun, is the same one given
airman applicants desiring a Statement of Dem-
onstrated Ability for the color vision require-
ment. The signal light gun test is administered
during daylight hours, but if an airman appli-
cant fails this test, his certificate is marked in-
valid for “night flight or by color signal control.”
The question arises as to how well these same
people would perform on the signal light gun
test if they were given the test again, this time
at night. Some of the subjects from the previous
study were retested on the practical test at night,
and the results were compared with their per-
formances on the clinical tests and the signal
light gun test given during daylight.

IL. Method.

A. Subjects. Men and women previously re-
cruited from a test booth at the 1968 Oklahoma
State Fair were part of the retest group. Ad-
ditional subjects were taken from a study em-
ploying active duty personnel at Tinker Air
Force Base, Oklahoma City. A total of 55 sub-
jects was used. They had all previously been
tested on seven clinical color vision tests and the
signal light gun test given during the day.

B. Tests and Procedures. Following is a de-
scription of the complete test battery given the
subjects in the previous studies.

1. The American Optical H-R-R Pseudo-iso-
chromatic plates?‘ consist of demonstration,

screening, and diagnostic plates. The subject
was instructed that there would be one, two,
or no figures on each plate. Failure on this
test was any error in plates 12 to 14. These
are the plates diagnosing a medium red-green
color deficiency.

2, The Dvorine Pseudo-Isochromatic plates
consist of 15 numerical plates, including one
demonstration plate. A failure for this test
was any error on 12 or more of the plates.

3. The Farnsworth Panel D-15 was de-
signed to differentiate the severe color defective
from the moderate color defective and the color
normal.® The test has 15 color plastic test
caps and one reference cap. The subject was
instructed to place each cap next to the one
most like it in color and to begin with the
reference cap. A failure was scored if there
were at least two cross-overs in approximately
the same direction on the seore sheet circle.

4, The Farnsworth-Munsell 100-hue test was
designed to measure color discrimination
among normals and areas of confusion in
people with color defective vision.’ The test
consists of four hinged boxes. The lid of each
box contains one-fourth of the 85 color test
caps randomly arranged. The bottom has two
fixed reference caps, one at either end. The
subject was told to take the test caps from the
lid and place them in the bottom half of the
box in order according to color. The failure
criterion was a calculated error score of 100
or more,

Each of the four previous tests was given
in a darkened room under a Macbeth easel
lamp equipped with a daylight filter. This
lighting approximates the C. I. E. source C.

5. The Color Threshold Test, developed by
the Air Force,’ consists of two vertically ar-
ranged discs, each containing eight filters,
placed in front of a test light. The upper disc
contains neutral density filters to vary lumi-



ACKNOWLEDGMENTS

The authors express their appreciation to Col. William F. LaFon for his
assistance in acquiring and testing military personnel at Tinker Air Force
Base, Oklahoma City, and also thank Maj. Gerald P. Ellsworth, Lt. Donald
Ashkenase, and Lt. Victor G. Hill for their generous assistance during the
testing procedures. The testing booth at the 1968 Oklahoma State Fair was
set up with the generous help of Dr. Harry L. Gibbons. We would especially
like to thank Dr. William E. Collins for his assistance and advice in the
preparation and completion of this study.


DAY

SIGNAL GUN TEST
P F

F .O73 29 .364
NIGHT
SIGNAL GUN TEST

P| .364 .273 .637
.437 564
® = .36*
N = 55

* Correlations are singnificant at the .Ol level.

Ficure 8. Contingency table showing the per cent of subjects who passed and failed the signal light gun test
under day and night conditions, The phi coefficient is also shown.

iL