Color Vision

Question 1

what is the definition of color vision

Answer 1

the ability to discriminate a light stimulus as a function of its wavelength

Question 2

what is the range of visible wavelengths that the eye can see

Answer 2

380-760 nm

Question 3

what type of energy causes photoreactions on the retina to experience vision

Answer 3

electromagnetic

Question 4

what is monochromatic light

Answer 4

colored light of a single wavelength

Question 5

how do we see “white” light

Answer 5

it is created by mixing all colors created by a prism with a convex lens

Question 6

what are the 3 additive primary colors

Answer 6

blue (435nm), green (545nm), and red (700nm)

Question 7

what do the additive primary colors produce

Answer 7

white

Question 8

what are the 3 subtractive primary colors

Answer 8

yellow, magenta-red, and cyan-blue

Question 9

which light rays mix to create the subtractive primary colors

Answer 9

any two-thirds of the spectrum

Question 10

what is subtractive color mixing

Answer 10

the mixing of color pigments or dyes

Question 11

what do the subtractive primary colors produce

Answer 11

black

Question 12

what are complementary colors

Answer 12

they have an additive mixture that forms white

Question 13

what are interference colors

Answer 13

color that results from interference on thin films (soap bubbles)

Question 14

why is the sky blue colored

Answer 14

the color was produced through the scatter of white light

Question 15

which wavelengths, longer or shorter, become scattered as the rays pass through the atmosphere

Answer 15

the longer wavelengths

Question 16

when do the sun’s ray’s give an intense red color

Answer 16

at sunrise and sunset, the sun’s ray’s pathlength is longer

Question 17

which direction do the sun’s rays pass though the atmosphere

Answer 17

vertically

Question 18

what is the shared chromophore in all visual pigments chemically related to

Answer 18

vitamin A

Question 19

what makes the rods and cone cell pigments different

Answer 19

different opsin proteins

Question 20

the genes encoding the opsin proteins are all members of what related receptor

Answer 20

G protein coupled receptors

Question 21

what are G proteins in rod and cone cells called

Answer 21

transducins

Question 22

are there different transducin forms for the different cone types

Answer 22

no they all share a common transducin form

Question 23

do rods and cones have the same transducin form

Answer 23

no they each have a specific form

Question 24

what reacts with an opsin protein to form a photoreceptor-pigment complex

Answer 24

11-cis isomer of aldehyde vitamin A

Question 25

if the chromophore is in the opsin-bound state what happens

Answer 25

it has unique properties that contribute to color vision functioning

Question 26

what is the opsin-shift

Answer 26

the change in absorption of the chromophore when it becomes bound to a particular opsin

Question 27

what cells are needed for scotopic vision

Answer 27

rod cells (dim light)

Question 28

what cells are needed for photopic and color vision

Answer 28

cone cells (bright-light)

Question 29

which cells are less sensitive, rods or cones

Answer 29

cones are less sensitive but they can mediate differentiation of colors

Question 30

what wavelength is the maximum for a rod response

Answer 30

510 nm

Question 31

how many light rays apart can humans distinguish light rays

Answer 31

2 monochromatic light rays (2nm apart)

Question 32

how many spectral colors does our color palette have

Answer 32

300 distinct spectral colors

Question 33

what type of cells are in the fovea

Answer 33

high density of cones, NO rods, for color vision

Question 34

what does the Young-Hemholtz theory emphasize

Answer 34

trichromacy

Question 35

what confirmed the Young-Hemholtz theory

Answer 35

the discovery of 3 cone photoreceptor systems

Question 36

what is the opponent theory (Karl Hering) based on

Answer 36

the hypothetical existence of three oppositional color pigment pairs

Question 37

what are the 3 channels produced by the signals from the 3 cone types that are combined at the level of neurons

Answer 37

red-green, blue-yellow, and black-white

Question 38

what is trichromatic vision

Answer 38

what our human vision is

Question 39

what are the 3 physiologic detection systems

Answer 39

the 3 classes of photoreceptor cells (represent the 3 additive primary colors)

Question 40

what are the 3 classes of photoreceptor cells

Answer 40

blue- short (s), green- middle (m), and red- long (L)

Question 41

does the response of a cone cells change depending on the energy of the photon that captures it

Answer 41

no the response is always the same

Question 42

what varies with photon energy

Answer 42

only the efficiency of a photon capture

Question 43

what relates to the rate of photon captures

Answer 43

the dynamic output

Question 44

what is the peak of the photopic curve

Answer 44

555nm

Question 45

what is the peak of the scotopic curve

Answer 45

505nm

Question 46

what does the scotopic curve represent

Answer 46

the photosensitivity of a single pigment rhodopsin

Question 47

what percentage of males in the US are affected by a red-green color deficiency

Answer 47

up to 10%

Question 48

what is the most common type of defect

Answer 48

deuteranomaly

Question 49

what is tritanopia

Answer 49

loss of the S-sensitive wavelength gene

Question 50

what is deuteranopia

Answer 50

loss of an M-sensitive wavelength gene, causes red-green defect

Question 51

what is protanopia

Answer 51

loss of L-sensitive wavelength gene, causes red-green defect

Question 52

what is a dichromat missing

Answer 52

missing one of three photopigments

Question 53

what is a deuteranope missing

Answer 53

missing chlorolable (CD)

Question 54

what is a protonope missing

Answer 54

erythrolabe (PE)

Question 55

what is a tritanope missing

Answer 55

cyanolabe (CT)

Question 56

what is a missing photopigment replaced with

Answer 56

other available pigments

Question 57

what are anamolous trichromats

Answer 57

they have all 3 photopigments but only one pigment is displaced

Question 58

if the color deficiency is congenital, will it be progressive

Answer 58

no

Question 59

what is acquired color deficiency

Answer 59

not inherited, secondary to disease (blue-yellow)- textbook, not always the case

Question 60

what is an achromatopia

Answer 60

the absence of multiple cone types and there is a severe loss in visual activity

Question 61

what is the ishihara test

Answer 61

a collection of pseudoisochromatic plates used as a diagnostic tool (most widely used diagnostic tool)

Question 62

what is an anomaloscope

Answer 62

an instrument used for precise follow-up testing

Question 63

when would a person develop an acquired color vision defect

Answer 63

disease or exposure to drugs or toxins

Question 64

what is an x-chrome CL

Answer 64

worn in one eye, reddish brown tint (patients may suppress that eye)

Question 65

what type of color deficiency is most severely affected

Answer 65

dichromats