This document provides an overview of color vision and color vision tests. It discusses the anatomy and physiology of color vision, including the three types of cones in the retina and the theories of color vision. It also describes different types of color vision defects including dichromacy, anomalous trichromacy, and monochromacy. The document outlines several types of color vision tests, including pseudoisochromatic plate tests like Ishihara plates, hue discrimination tests like the Farnsworth Munsell 100 Hue Test, spectral anomaloscopes, and lantern tests. The goals, administration, and interpretation of these clinical color vision tests are summarized.

1. COLOR VISION TESTS
Dr Saurabh Kushwaha
Resident Ophthalmology

2. SCOPE
 Color vision
 Color attributes
 Classes of cones
 Color vision defect
 Color vision tests
 Photochromatic plate tests
 Hue discrimination tests
 Spectral anomaloscopes
 Lantern tests

3. COLOR VISION
 Color vision is the subjective sensory
phenomena ability of the eye to discriminate
between colors excited by lights of different
wavelengths
 Function of cones
 Not an inherent property of the object
 Internal construct of an individual:
wavelength of the light entering and structure
of the eye

4. SPECTRUM OF LIGHT

5. TYPES OF COLORS
 Primary colors
 Additive colors/ Negative of primary
 Complementary colors
 Metamers

6. COLOR ATTRIBUTES
 HUE
Determined by the wavelength of light absorbed & reflected by
the object
 SATURATION
Purity of color
It can be estimated by measuring how much of a particular
wavelength must be added before it is distinguishable from
white
The more the wavelength required to be added to make the
discrimination the lesser the saturation
 BRIGHTNESS
Depends upon luminosity of the component wavelength
The wavelength shift of maximum luminosity from photopic to
scotopic viewing is called Purkinje shift

7. COLOR ATTRIBUTES

8. TYPES OF VISION
 Achromatic
• Sensation of white vision with no color vision
 Chromatic
• Spectral color vision
• Extra spectral color vision

9. CLASSES OF CONES
1st Class 2nd Class 3rd Class
SWS receptors MWS receptors LWS receptors
4% in retina 32% in retina 64% in retina
Blue cones Green cones Red cones
Most sensitive to
blue violet
Most sensitive
to green
Most sensitive to
greenish- yellow

10. CLASSES OF CONES

11. CHARACTERISTICS OF CONES

12. THEORIES OF COLOR VISION
 Young-Helmholtz theory of color vision
(Trichromatic color theory)
 Hering’s opponent color theory
 Donders’s zones theory

13. COLOR VISION DEFECT
 Faculty to appreciate one or more primary
colors is either defective (anomalous) or
absent (anopia)
 Color blindness is also called
as Daltonism (John Dalton was
deuteronope)

14. TYPES OF COLOR VISION DEFECT

15. CONGENITAL DEFECTS

16. ANOMALOUS TRICHROMACY
 Partial deficiencies in one of the three cone pigments
 Phenotypically mild
1. Protanomaly (protanomalous trichromacy)
The red spectrum is displaced towards shorter
wavelength

17. 2. Deuteranomly (Deuteranomalous trichromacy)
• The chlorolabe spectrum is displaced towards
longer wavelength
3. Tritanomaly
• Very rare
• Blue-green and yellow-green insensitivity
• Cone pigment for blue defective

18. DICHROMACY
 Lack one type of cone function completely
 Match colors with a mixture of two primaries
 Defect is more severe
 Types: Depending on which cone pigment is missing
1. Protanopia
• Most common
• 1% male, 0.02% female
• Lack the long-wave ‘red’ sensitive receptors
• Red - brown confusion

19. 2. Deuteranopia
• 1% male, 0.01% female
• Lack the middle-wave ‘green’ sensitive receptors
• Green - brown confusion
3.Tritanopia
• Very rare
• 0.01% of male, 0.03% of female
• Lack the short-wave ‘blue’ sensitive cones
• Blue - green and yellow - violet confusion

20. DICHROMACY

21. ACHROMATOPSIA
CONE
MONOCHROMACY
 Prsence of only one
primary color cone
 Gray scale vision with
no combination of colors
 2 types –
• L/M cone present: AR
• S cone present: X
linked
 Acuity 6/18 to 6/60
ROD
MONOCHROMACY
 Complete absence of
cones, AR
 1 in 30,000
 Features
• Total color blindness
• Pendular nystagmus
• Low vision, 6/60
• Photophobia
• Normal Fundus

22. ROD MONOCHROMACY

23. ACQUIRED COLOR VISION DEFECTS
 Defects due to ocular disease, side-effect of
medication, consequence of toxic poisoning or head
trauma
 Occurs due to disruption of the neural pathway
between the eye and the vision center of the brain
rather than by the loss of cone function in the eye
 Ex: Brain damage : Achromatopsia
Diabetic Retinopathy : Tritanopia
Ethambutol toxicity : Deuteranopia
Stargardt’s disease : Protanopia

24. KOLLNER’S RULE
Red-Green deficiencies in
optic nerve lesions
resembling protan-
Deutan
 Optic neuritis
 Leber’s optic atrophy
 Toxic amblyopia
 Cone dystrophy
 Stargardt’s disease
 Best disease
Blue-yellow deficiencies in
retinal lesions resembling
Tritan
 Diabetic retinopathy
 ARMD
 RP
 Myopic retinal
degeneration
 Early Glaucoma
 Autosomal dominant optic
atrophy
 Papilledema

25. COLOR VISION TEST
 There are a number of clinical color vision
tests which aim:
• Identity
• Classify
• Grade the severity of color vision defect
• Determine the occupational suitability

26. TYPES OF COLOR VISION TESTS

27. INDICATIONS
 All children at their first eye test
 History suggest impaired color discrimination
 For occupational purposes
 Suspected acquired color vision defect as a
result of an ocular or systemic disease, or a
side effect of medication or injury

28. PSEUDOISOCHROMATIC PLATES
 To identity a colored symbol made up of colored
dots of varying sizes embedded in a background of
differently colored dots
 The figure and the background colors are chosen
so that they are confused (isochromatic) by color
deficient but discerned by the normal person
 The difference between the colors should exceed
the minimum required for them to be discriminated by
person with normal color vision
 Examples –Ishihara plates (red-green defect),
Hardy Rand Rittler (HRR) ( both red-green defect and
blue defect)

29. ISHIHARA PLATES
 Jacob Stilling, German scientist (1873)
 Detection of presence of protan/deutan
 Symbol recognition by discrimination of either
hue or saturation
 Currently available editions are - 38, 24 and 14
plate version

30. CRITERION FOR TESTING
 Proper illumination (natural day light )
 Visual acuity, > 6/60
 Patient should use his/her near correction
 Field of vision
 Testing Distance: 75 cm for plate
 Observation time is 3 to 5 secs per plate (10 secs
for winding paths)
 Monocular testing
 Plane of paper is right angle to line of vision
 Store plates inndark when not in use

31. ISHIHARA TEST

32. ISHIHARA TEST

33. ISHIHARA TEST

34. TEST INTERPRETATION

35. HUE DISCRIMINATION TESTS
 Qualitative test for hue discrimination-color
samples in small caps to be arranged according
to hue
 Useful in acquired colour vision abnormalities
 Diagnosis of the type and degree of color vision
defect
 Cannot distinguish between dichromats and
anomalous trichromats
 Manual dexterity is required so unsuitable in
children

36. FRANSWORTH MUNSELL 100 HUE
TEST
 Consists of 4 boxes, 85 caps with 2 piolt caps at
the end of each box
 Patient arranges caps in natural order according
to color/ hue
 Takes 15 – 30 mins in total
 Main purpose
• to classify type of CVD
• to measure the severity
• to assess the progression of an acquired CVD

37. FM 100 HUE TEST

38. TEST INTERPRETATION

39. TESTING AND ERROR SCORE

40. TEST INTERPRETATION

41. FRANSWORTH DICHOTOMOUS
D-15 TEST
 Shorter veraion of Fransworth Munsell 100 Hue
Test with 15 caps
 Single fixed reference cap
 15 movable color caps sampling a complete
color circle

42. FD PANEL D-15 TEST
 Because of large differences in color of adjacent
caps it evaluates major color confusion of
severe R-G or B -Y defects
 Done after the color vision defect has been
indicated by fail on the Ishihara plates
 Detects individuals with moderate – severe
dyschromatopsia

43. TEST INTERPRETATION
 Score is plotted on paper as arrangement of caps
 Correct: semi circle; Error: crossed lines
 Axis of lines determine the type of color deficiency

44. SPECTRAL ANOMALOSCOPES
 Specifically developed and most sensitive to
diagnose congenital color deficiency
 Most provide a Rayleigh match  red added to
green to produce yellow test color
 Some have Moreland match  blue added to
green to make blue-green test color
 Extensive training required by the administrator
• Nagel
• Besancon
• Pickford-Nicolson

45. NAGEL’S ANOMALOSCOPE
 Uses Rayleigh equation
 Circular bipartite field (tests 2-3 degree, foveal
cones)
 Subject matches lower yellow test field by tuning
the quantities of red and green light in upper field

46. TEST INTERPRETATION
 Subject is asked to comment on whether upper and
lower fields are same color
Deuteranomalous trichomats  upper field is too red
Protanomalous trichomats  upper field is too green
 Adjust red/green to match yellow ( green > greenish-
yellow > yellow > orange > red)
 Luminosity of yellow can be altered
 Check range of match by altering ration in one –unit
steps

47. TEST INTERPRETATION
 Examiner determines range of red-green ratios
that produce an acceptable match and required
brightness of lower field
 Anomalous quotient - A546/A670 for subject
divided by A546/A670 for admin
 Normal: 0.74 - 1.33

48. TEST INTERPRETATION
 Normal subject
matches in a narrow range
a scale of 0 (pure green) to 73 (pure
red) & the normal match will be
around 42 units
 Protans
turn down the intensity of yellow
light when matching the field to the
Red one
 Deutans
turn up the intensity of yellow light
when matching the field to the Red
one

49. TEST INTERPRETATION
 Values recorded from both red-green and luminance dial
 Normal subjects narrow range of accepted values
 Anomalous subjects wider range
 Dichromats  widest possible range
 Luminance setting differentiate protan from deutan subjects
Protanoscopes match by lowering luminance of yellow field
Deuteranopes have a luminance function much closer to
normal

50. LANTERN TESTS
 Measure if subject can perform colour signal
recognition with adequate proficiency to maintain
safety standards
 Subject is asked to identity the color of a signal light in
lantern
 Used in maritime, air and railway industries
 Speed and sequence of colour presentation
determines efficacy of test
 Farnsworth lantern
 Beyene latern
 Glies-Archer lantern
 Edridge-Green lantern

51. FARNSWORTH LANTERN TEST
 Usually done at 6 metre distance
 Simulate colour vision demands under working
conditions
 Nine possible combinations of 3 colors - red, green
and white in the two positions
 A patient must tell average 8 out of 9 correct
responses to pass the test

52. SUMMARY

53. THANK YOU