Short Quiz on COLOUR VISION & COLOUR BLINDNESS
Instruction
2. There is 1 Mark for each correct Answer
Blue and green
Red and green
Blue and yellow
True about color blindness
Age related
Hereditary
Males only
Female only
True about color blindness:
More common in male
More common in female
Age related
b and c
A person has defective blue colour apprec-iation. His condition is better named as
Deuteranomalous
Deuteranopia
`Tritanopia
Tritanomalous
Protonopes have defect in identifying which colour
Red
Blue
Green
Black
Any spectral colour can be matched by a mixture of three monochromatic lights (red, green, blue) in different proportions. If a person needs more of one of the colour for matching than a normal person, then he has a colour anomaly. More red colour is needed in the case of :
Deuteranomaly
Tritanomaly
Protonomaly
Tritanomaly
Regarding color blindness true:
Mainly congenital
Can be testes with Fansworth 100 hue test
Isihara chart test red/green color blindness
All
Congenital colour blindness is transmitted as:
Recessive disorder
Autosomal dominant
Sex-linked disorder
All of the above
Acquired blue blindness is a feature of:
Increased sclerosis of the crystalline lens
Disease of optic nerve
Disease of macula
All of the above
Most common type of colour blindness is:
Protanopes
Deuteranopes
Tritanopes
None
A person has defective blue colour appreciation. His condition is better named as-
Deuteranomalous
Deuteranopia
Tritanopia
Tritanomalous
The colours best appreciated by the central cones of our foveo-macular area are :
D i.e. Blue & yellow
Macular lesion tends to produce blue-yellow Q defects and optic nerve lesions produce red green defects Q
True about color blindness
B i.e. Hereditary Colour Blindness (Achromatopsia)
- An individual with normal colour vision is k/a trichromate. In colour blindness, faculty to appreciate one or more primary colours is either defective (anomalous) or absent (anopia). It may be congenital or acquired.
- Colour blindness is usually a hereditary condition that is present by birth, and though it is more common in males, it can occur in females also. It can also be an acquired condition through diseases of optic nerve or macula but is not normal age-related phenomena. There is no treatment.
- Red & green pigment cones are coded on X-Chromosome and Blue cones on Chromosome 7.
A i.e. More common in males
A person has defective blue colour apprec-iation. His condition is better named as
D. i.e. Tritanomalous
Suffix \”anomalous\” is used for defective colour vision & Suffix \”anopia\” is for absent colour vision.
|
Term |
Meaning |
|
Nyctalopia |
Night blindness |
|
Hamarlopia |
Day blindness |
|
Achromatopsia |
Colour blindness |
|
Trichromate |
Individual with normal colour vision |
|
Protanomalous |
Defective red colour appreciation |
|
Deuteranomalous |
Defective green colour appreciation |
|
Tritanomalous |
Defective blue colour appreciation |
|
Protanopia |
Complete red colour blindness |
|
Deuteranopia |
Complete green colour blindness |
|
Tritanopia |
Complete blue colour blindness |
- So anopics have dichromatic colour vision i.e. (are able to see two primary colours) & anomalous have trichromatic colour vision with anomaly (i.e. mechanism to appreciate all 3 primary colours is present but is defective for one or two of them)
- Protan means first, deutan means second, and tritan means third. According to decreasing wavelength it is used for red (550-570 nm, so protan), green (520-540 nm, so deuteran) and blue (410-424 nm, so tritan).
A i.e. Red
Any spectral colour can be matched by a mixture of three monochromatic lights (red, green, blue) in different proportions. If a person needs more of one of the colour for matching than a normal person, then he has a colour anomaly. More red colour is needed in the case of :
C i.e. Protonomaly
Regarding color blindness true:
A i.e., Mainly congenital B i.e., Can be tested by Farnsworth 100 hue test; C i.e. Ishihara chart test red/ green colour blindness
Tests for color vision
Pseudoisochromatic charts
– Ishihara plates mainly to screen congenital protan & deuterans (i.e., red & green defects)Q
– Hardy -Rand – Rittler plates is more sensitive to Ishihara since it can defect all three congenital defects
- Edridge Green lantern test : the subject has to identify various colours shown to him (in lantern) & judgement depends on mistake he makes.
- City university test : a spectroscopic test where subject is asked to match central colour to its closest hue from 4 peripheral surrounding colour in each of 10 plates.
- Fansworth Munsell 100 hue test is the most sensitiveQ for both congenital & aquired colour defects. It
consists of 85 hue caps (not 100) and vision is judged by error score i.e., higher score = poorer vision. - Fansworth D 15 hue discrimination test is similar test but utilizes only 15 hue caps
- Nagel\’s anomaloscope (asked to mix red & green to make a given shade)
- Holmgren\’s wool testQ
Ans. Sex-linked disorder
Acquired blue blindness is a feature of:
Ans. Increased sclerosis of the crystalline lens
Most common type of colour blindness is:
Ans.B. Deuteranopes
Red-green color blindness is the most common type of color deficiency. Also known as deuteranopia, this is most likely a congenital condition.
A person has defective blue colour appreciation. His condition is better named as-
For defective (anomalous) colour vision, suffix anomalous is used; and for absent colour suffix anopia is used.
|
Colour |
Defective |
Absent |
| Green | Deuteranomalous | Deuteranopia |
| Red | Protanomalous | Protanopia |
| Blue | Tritanomalous | Tritanopia |