the human eye

Question 1

the cornea (located ______) causes _____ refraction than the lens

Answer 1

on outside / more

Question 2

the cornea refracts the light _______ way, ________________

Answer 2

the same / regardless of the location of the object

Question 3

the lens can _______ and _________, allowing it to focus light from both nearby and distant objects on ______

Answer 3

change shape / refract light / retina

Question 4

the human eye forms a ____ and ______ image on the retina, but the brain processes the images it receives and gives you sense that it is ________

Answer 4

real / inverted / upright

Question 5

which parts of the eye are responsible for detecting colour (in retina)?

Answer 5

cones

Question 6

which parts of the eye are responsible for detecting light (in retina)?

Answer 6

rods

Question 7

the human eye can detect which colours best?

Answer 7

red, blue, green

Question 8

what causes the “after image”?

Answer 8

overstimulation of photoreceptors in the eye

Question 9

what is the iris?

Answer 9

coloured part of eye surrounding pupil; lies between cornea and lens

Question 10

what is the function of the iris?

Answer 10

widens/narrows pupil to control amount of light entering eye

Question 11

what is the pupil?

Answer 11

round, dark centre of eye

Question 12

what is the function of the pupil?

Answer 12

opens and closes to regulate amount of light reaching retina

Question 13

what is the cornea?

Answer 13

clear part of eye covering iris and pupil

Question 14

what is the function of the cornea?

Answer 14

lets light into eye, permitting sight

Question 15

what is the lens?

Answer 15

round, spherical body in eye; located behind cornea

Question 16

what is the function of the lens?

Answer 16

focuses light rays into retina

Question 17

what is vitreous gel?

Answer 17

part of eye between lens and retina; clear (to allow light to pass through) jellylike substance

Question 18

what is the function of the vitreous gel?

Answer 18

helps maintain structural stability of eye and retinal health but can be removed without harming vision

Question 19

what is the optic nerve?

Answer 19

nerve carrying electrical impulses from photoreceptor cells (rods and cones) in retina to visual cortex in brain; located at back of eye

Question 20

what is the function of the optic nerve?

Answer 20

transmits signals to brain to be converted to images

Question 21

what is the retina?

Answer 21

sensory membrane lining eye

Question 22

what is the function of the retina?

Answer 22

receives images formed by lens and converts them into signals that reach the brain via optic nerve

Question 23

what is the sclera?

Answer 23

the white of the eye

Question 24

what is the function of the sclera?

Answer 24

protective covering

Question 25

what is the "blind spot"?

Answer 25

the point of entry to the optic nerve on the retina; insensitive to light

Question 26

what is peripheral vision?

Answer 26

the part of vision occurring outside the very centre of the field of view

Question 27

what is myopia?

Answer 27

when the eyeball is too long: light rays converge at a focal point before reaching the retina= farther images are blurry

Question 28

how can myopia be treated?

Answer 28

using a diverging lens to bend light rays to meet after reaching the cornea

Question 29

what is hyperopia?

Answer 29

when the eyeball is too short: light rays converge at a focal point behind the retina= closer images are blurry

Question 30

how can myopia be treated?

Answer 30

using a converging lens to bend light rays to meet before reaching the cornea

Question 31

which is myopia and hyperopia with respect to nearsightedness and farsightedness?

Answer 31

``` myopia = farsightedness hyperopia = nearsightedness ```

Question 32

what is astigmatism?

Answer 32

a condition in which the cornea is slightly cone shaped rather than spherical

Question 33

what is presbyopia?

Answer 33

a condition caused by loss of elasticity in the lens (eye muscles become stiff and ciliary muscles can no longer shape lenses); cannot focus on nearby objects

Question 34

how can presbyopia be corrected?

Answer 34

bifocals

Question 35

how can astigmatism be corrected?

Answer 35

toric lenses or surgery

Question 36

what are the 3 steps to laser eye surgery?

Answer 36

cut a thin flap in cornea; pull back alblate surface into desired shape replace flap

Question 37

pros to laser eye surgery

Answer 37

improved vision | less need for glasses/contact lenses

Question 38

cons to laser eye surgery

Answer 38

``` dry eyes oversensitivity to light poor perception of contrast double vision perception of ghosted images, starbursts, halos around light sources ```