Chapter 3

Question 1

transparent layer forming the front of the eye

Answer 1

cornea

Question 2

transparent focusing element of the eye

Answer 2

lens

Question 3

receptor in the retina that is responsible for vision at low levels of illumination

Answer 3

rod

Question 4

receptor in the retina responsible for color vision and detail vision

Answer 4

cone

Question 5

bundle of nerve fibers that carry impulses from the retina to the lateral geniculate nucleus

Answer 5

optic nerve

Question 6

small area in the human retina that contains only cone receptors

Answer 6

fovea

Question 7

clinical condition that causes decay of an area of the retina that includes the fovea and a small surrounding area

Answer 7

macular degeneration

Question 8

retinal disease that causes a gradual loss of vision, beginning in the peripheral retina

Answer 8

retinitis pigmentosa

Question 9

small area where the optic nerve leaves the back of the eye

Answer 9

blind spot

Question 10

act of bringing objects located at different distances into focus by changing the lens shape

Answer 10

accommodation

Question 11

distance between one peak of a light wave and the next peak

Answer 11

wavelength

Question 12

band of electromagnetic energy that activates the visual system and that, therefore, can be perceived

Answer 12

visible light

Question 13

inability of the eye to accommodate due to hardening of the lens and weakening of the ciliary muscles

Answer 13

presbyopia

Question 14

inability to see distant objects clearly

Answer 14

myopia

Question 15

nearsightedness in which the cornea and/or the lens bends the light too much

Answer 15

refractive myopia

Question 16

nearsightedness in which the eyeball is too long

Answer 16

axial myopia

Question 17

change in shape of the retinal part of the visual pigment molecule; occurs when a quantum of light is absorbed

Answer 17

isomerization

Question 18

condition in which people can see object that are far away but do not see near objects clearly

Answer 18

hyperopia

Question 19

usually taken as the starting point for the dark adaptation curve

Answer 19

light-adapted sensitivity

Question 20

increase of eye’s sensitivity to light when light in the room decreases

Answer 20

dark adaptation

Question 21

condition in which the retina is detached from the back of the eye

Answer 21

detached retina

Question 22

acuteness of visual receptors to different parts of the visible spectrum

Answer 22

spectral sensitivity

Question 23

function relating a subject’s sensitivity to light to the wavelength of the light

Answer 23

spectral sensitivity curve

Question 24

curve plotting visual sensitivity vs wavelength for rod vision

Answer 24

rod spectral sensitivity curve

Question 25

plot of visual acuteness vs wavelength for cone vision

Answer 25

cone spectral sensitivity

Question 26

movement from cone spectral sensitivity to rod spectral sensitivity that takes place during dark adaptation

Answer 26

Purkinje shift

Question 27

occurrence when many neurons synapse onto a single neuron

Answer 27

neural convergence

Question 28

ability to resolve small details

Answer 28

visual acuity

Question 29

area on the receptor surface that, when stimulated, affects the firing of that neuron

Answer 29

receptive field