Color Vision Testing

Color Vision Testing Bernard R. Blais, M.D. Clinical Professor Albany Medical College Albany, New York Blais Consulting, Ltd. 4 Innisbrook Drive Clifton Park, NY 12065 Phone: (518) 371-8147 Fax: (518) 373-9347 Email: bblais@nycap.rr.com Disclosure: Book Royalty Publisher New Color Vision Book, RPI Publishers, Atlanta, GA

Who is doing color vision testing?

What are you testing for?
Congenital deficiencies

Acquired deficiencies

Both

Who is using the Ishihara Plates for testing color deficiencies? What is it testing?

Who utilizes the color vision testing in the Titmus Equipment Stereo Optical Equipment Armed Forces Screening

What color test is utilized?

Ishihara plates

What do they test for?
Red deficiencies
Green deficiencies

Does color defect really cause a difference? Websafe selection. The 27 normal colours have been produced by all combinations of 0, 50, and 100% levels of red, green and blue primaries. They have then been transformed to show their appearance to colour-blind viewers. McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002 Figure 30.

Visual Spectrum Defects
Three primary colors
Blue
Green
Red

Retinal cones
Contain classes of photo pigment
Overlapping spectral sensitivity
Have maximum sensitivity in the spectral regions
Classic photo pigment

Color Defects Trichromatic Theory
All spectral hues matched by mixture of three primary colors
Short Wave – Blue
Medium Wave – Green
Long Wave – Red

Trichromatic Theory
Mariotte (1681)
Newton (1704)
All colors could be matched by three others.
Cut-away view of the Munsell solid. McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002 Figure 6 as modified from Britannica® DVD2000 © 1994-2000 Encyclopedia Britannica, Inc.

So what does one actually see with each of these deficiencies?

Color normal Blue blind

Color normal Green blind

Color normal Red blind

Websafe selection. The 27 normal colours have been produced by all combinations of 0, 50, and 100% levels of red, green and blue primaries. They have then been transformed to show their appearance to colour-blind viewers. McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002 Figure 30.

How does this affect the individual’s ability?

Another example of how color might appear with normal color vision on the left, and the same objects as they might appear with a color deficiency on the right.

Traffic lights as seen with normal color vision on the left and, as they might appear with some types of color vision deficiency on the right.

The Nomenclature of Color Vision Deficiencies Table I Incidence of Color Defects in Caucasian Males Heredity % (1) Trichromatism (a) normal 91.8 (b) anomalous - (i) protanomaly 1.0 (ii) deuteranomaly 4.6 (iii) tritanomaly 0.0001 (2) Dichromatism (a) protanopia 1.2 (b) deuteranopia 1.4 (c) tritanopia 0.0001 (3) Monochromatism (a) of the rods 0.003 (b) of the cones 0.000001 Acquired (a) triton (blue-yellow) possibly 5% (b) proton (red-green) Duke Elder, S., Gloster, J. Weale, R. Physiology of The Eye, Chapter XVI on Color Vision, page 616, 1968 Table XIV and Birch, Jennifer, Diagnosis of defective color vision, Oxford University Press (1993).

Simplified terminology for the standard poorly understood color deficiencies
TABLE 2
Formal Term New Term
protanopic red-blind
deuteranopic green-blind
tritanopic blue-blind
protanomalous red-weak
deuteranomalous green-weak
tritanomalous blue-weak
achromatic achromatic
McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002 Table 7 as modified from ©Transport for London. Reproduced by kind permission of London’s Transport Museum.

Available Color Vision Testing Techniques
Pseudoisochromatic Plates
Most widely used
Example is Ishihara and HHR test
Each plate made of
Irregular color dots
Concealed hidden figure
Rapid screening between normal and deficiencies

Available Color Vision Testing Techniques 10 min. 10 min. 6000 Classify and grade red-green defects Rarely used Anomaloscope (Nagel) Prototypes Not standardized to requirements. Prototype under under develop- development. ment. Computer-Based Tests <5 min. 1 hour >10 min. < 5 min. PATIENT TIME Test occupational requirement Discrimination Discrimination Severity INDICATION < 5 min. <500 Widely used Pseudoisochromatic Plate <5 min. 3000 Used in screening persons for RG Standard test Lantern (Falant) 1 hour >10 min. 900 350 Very selective Medical Research Arrangement Test – Hues FM 100 D 15 TECH TIME EQUIPMENT COST FREQUENCY USED

Available Color Vision Testing Techniques R.G. No Optical equipment Anomaloscope (Nagel) R.G.B Yes Plate of irregular dots Pseudoisochromatic Plate Not standardized to requirements. Prototype under development. Computer-Based Tests R.G.White Yes One to three lights Lantern (Falant) R.G.B. Identify moderate Severe capabilities Classify R.G.B. abnormalities Yes No No Color disks (caps) 100 15 Arrangement Test – Hues FM 100 D 15 GRADING TESTS SCREENER DESIGN

Arrangement Test
Consist of colored discs (cap)
Color change from one cap to another
Arranged color changes in order
The 100 Hue arrangement test - Photo courtesy of Richmond Products.

Illumination Hue Discrimination Arrangements, PIC Tests
Appearance pigment colors change by illumination.
Ishihara plates results altered by Tungsten light
Pass unqualified
CIE – standard source required.
Insert Figure 20 from manuscript

Available Color Vision Testing Techniques R.G No Optical equipment Anomaloscope (Nagel) R.G.B Yes Plate of irregular dots Pseudoisochromatic Plate Not standardized to requirements. Prototype under development. Computer-Based Tests R.G.White Yes One to three lights Lantern (Falant) R.G.B. Identify moderate Severe capabilities Classify R.G.B. abnormalities Yes No No Color disks (caps) 100 15 Arrangement Test – Hues FM 100 D 15 GRADING TESTS SCREENER DESIGN

Anomaloscope (Nagel)
Used to classify and grade red-green defects
Balance of red-green to yellow

Lantern Tests
Try to test the safety needs for actual jobs.
Stereo Optical Optec 900

Available Color Vision Testing Techniques 10 min. 10 min. 6000 Classify and grade red-green defects Rarely used Anomaloscope (Nagel) Prototypes Not standardized to requirements. Prototype under under develop- development. ment. Computer-Based Tests <5 min. 1 hour >10 min.. < 5 min. PATIENT TIME Test occupational requirement Discrimination Discrimination Severity INDICATION < 5 min. <500 Widely used Pseudoisochromatic Plate <5 min. 3000 Used in screening persons for RG Standard test Lantern (Falant) 1 hour >10 min. 900 350 Very selective Medical Research Arrangement Test – Hues FM 100 D 15 TECH TIME EQUIPMENT COST FREQUENCY USED

Computer-Based Tests
Just being developed in several laboratories
Some based on
Conventional diagnostic tests
Others explain the new medium

Acquired Color Vision Defects Resulting from Ocular Pathology
Intracranial injury
Excessive use of therapeutic drugs
Chemical toxicological effects

Chemical
Chemical toxicological effects seen
Xylene, toluene toxicity
Blue-yellow color deficiency present prior to findings of peripheral neuropathy
At what toxic level does the color vision defect found
more research needed?

Basic Requirements of Color Vision Screening
Must be able to evaluate Red.Green.Blue hues
Must be technically simple to operate
Must take short period to complete
(1-2 minutes maximum)
Technician/nurse time normally 5 minutes.
Must be inexpensive to purchase test and special illumination

What test fulfills these requirements? The function of different types of color vision tests Classification and Screening tests grading tests Diagnostic tests Vocational tests 1. Anomaloscopes 1. Anomaloscopes 1. Anomaloscopes and psychophysical tests 2. Pseudoisochromatic 2. Some pseudo- plates isochromatic plates 3. Hue discrimination 1. Hue discrimination (or arrangement) tests (or arrangement) tests 2. Lanterns

What test fulfills these requirements?
The principal color vision tests in each design category
Pseudoisochromatic Hue discrimination
Anomaloscopes plates (or arrangement) tests Lanterns Others
Nagel Ishihara Farnsworth D15 (a) Paired lights TNO test
Holmes-Wright Cit University test
Neitz American Optical Co. Desaturated D15 Falant
Besançon (Hardy, Rand & Ritter) (Adams & Lanthony)
Pickford-Nicholson Tokyo Medical College 28 Hue (b)Single lights Sahlgren’s test
Dvorine 40 Hue Edridge-Green Oscar test
F2 Plate Giles-Archer
Velhagen Farnsworth-Munsell Color-threshold
Ohkuma 100 Hue tester
American Optical Co.
(13375)
Bostrum-Kugelberg
Standard pseudiosochromatic
plates 1st & 2nd editions
Lanthony tritan album

Printed Pseudoisochromatic Plates
Most widely used screening for color vision
Most design to detect congenital Red-Green
Only four tests – detects tritan (blue defects)

Goal in Occupational Medicine
A screening test that screens for
Red
Green
Tritan (blue – yellow)

Screening Test in Vision Screeners Armed Forces Titmus Stereo Optical
Ishihara Test
Screens for only red and green

AO HRR Plates
American Optical’s original
Hardy, Rand, Ritter Plates

HRR Plates
Consist of background colored circles
Range of size and lightness
HRR indicates severity of defect of any RG defect
Screen for tritan (blue-yellow)

HRR Plates
By itself can determine integrity of three hues
Red
Green
Blue

Two HRR Plates Acceptable
Original American Optical Plates (1954)
Richmond Products, Inc. Fourth Edition only (2002)

HRR Diagnosis of Color Deficiency Diagnosis based on HRR results Type HRR Extent: Passes Screener Mild Medium Strong Frequency Protan Minimal Affect Anomalous Anomalous Protanope 25% Protan Protan Deutan Minimal Affect Anomalous Anomalous Deuteranope 75% Deutan Deutan Tritan Minimal Affect Anomalous Anomalous Trianope trace Comparison with Color Chip tests Farnsworth D15 Passes Passes Fails Fails N/A L’Anthony D15 Passes Fails Fails Fails N/A Informational Brochures of Richmond Products Resources 2007.

Alternate Test
Two tests needed to identify Red-Green defects and tritan (blue-yellow)

Tests used for evaluation of congenital color deficiency (modified) Function Scope Tests Screening red-green defects Ishihara plates blue defects CU (City University) tritan plates HRR plates Screening & grading Ishihara + CU tritan plates HRR plates D15 test, Anomaloscope Evaluation D15, FM100 Anomaloscope Occupational transport & armed Ishihara plates screening services Falant McIntyre, D, Color Blindness Causes and Effects, Dalton Publishing, Chester, England, 2002, p. 81.

Confused?
Yes – When I started to evaluate this subject, books were all too complicated for occupational medicine.
Tasking of dyschromatopsia by ACOEM’s Council on Scientific Affairs to
Sensory Perception Committee
to explore the evidence for toxicological acquired color deficiency.

Do you want your employees having the “activities of daily living” working with these defects?

What do you want the employees to see where color vision is a mandatory requirement?

B. Red-Blind A. Color Normal Fruit stall. A fruit stall as seen by a color normal (A) and red-blind (B). McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002. Figure 32.

C. Green-Blind A. Color Normal Fruit stall. A fruit stall as seen by a color normal (A) and green-blind (C). McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002. Figure 32.

D. Blue-Blind A. Color Normal Fruit stall. A fruit stall as seen by a color normal (A) and blue-blind (D). McIntyre, D., Color Blindness Causes and Effects, Dalton Publishing, Chester England, 2002. Figure 32.

Dr. Maureen Neitz

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Color Vision Testing

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