14. Color perception. Color deficiencies. Methods for evaluation

Question 1

what is colour preception?

Answer 1

the ability of an organism to distinguish objects based on the wavelength of light reflects , emit or transmit

Question 2

what is the physiology of colour preception ?

Answer 2

begins with retinal cells - cone cells

Question 3

what type of colour vision do we have

Answer 3

trichromatic

Question 4

what are the three different cone types ?

Answer 4

S - 400-500nm, peak 420-440
M -450-630nm peak 534-555
L 500-700nm peak 564-580nm

Question 5

yellowish green light stimulate which cone ?

Answer 5

stimulates L and M cone equally

Question 6

red light stimulate which cones

Answer 6

more L then M and S

Question 7

blue lg. stimulate which cones ?

Answer 7

S cones more strongly

Question 8

how can we have reception of different wavelength of light ?

Answer 8

brain combines information from stimulation of each type of receptors

Question 9

colour deficiency usually affects whom ?

Answer 9

men

due to changes in Xchromosomes

Question 10

what is the problem with colour deficiency ?

Answer 10

problem in the development of one of the sets of cones
monochromasy - total colour blindness
dichromacy - one of the three basic colour is absent
anomalous trichromasy - one of the three cone pigment is altered

physical or chemical damage
NO CURE

Question 11

in almost all cases of colour deficiency the patient can retain discrimination of which colours ?

Answer 11

blue - yellow

Question 12

what is partial colour blindness ?

Answer 12

difficulty to distinguish between red and green

yellow and blue

Question 13

what is the method for evaluating colour deficiency ?

Answer 13

ishihara test

series of pictures with colour spots