Eye

Question 1

what is the sclera?

Answer 1

the white part of the eye that forms tough, supporting outer cover

Question 2

what is the iris?

Answer 2

circular and radial muscles that control the size of the pupil and therefore how much light enters the eye

Question 3

what is the pupil?

Answer 3

hole in the eye to allow light to enter

Question 4

what is the retina?

Answer 4

light receptive cells

Question 5

what is the cornea?

Answer 5

transparent outer layer that protects the eye and HELPS refract the light

Question 6

what is the lens?

Answer 6

a hard ball of jelly that REFRACTS rays of light and FOCUSES them onto the retina

Question 7

what is the job of the cilary muscles?

Answer 7

they contract or relax to change the thickness of the lens

Question 8

what is the suspensory ligament?

Answer 8

ligaments that hold the lens in place

Question 9

what is the optic nerve?

Answer 9

carries impulses from the receptors in the eye to the brain

Question 10

why do our eyes need to adapt to light?

Answer 10

protection

Question 11

how do our eyes adapt to dim light?

Answer 11

circular muscles relax
and radial muscles contract
so the pupil becommes bigger and more light enter the eye

Question 12

how does the eye adapt to bright light?

Answer 12

circular muscles contract
radial muscles relax
so the pupil becomes smaller and less light enters the eye

Question 13

what is accomodation?

Answer 13

the ability to change shape of the lens and focus on near or distant objects

Question 14

how does the accomodate to see near objects?

Answer 14

ciliary muscles will contract and so the suspensory ligaments loosen making the lens thicker and refracts the light more

Question 15

how does the eye accomodate to see far objects?

Answer 15

the ciliary muscles relax so the suspensory ligaments tighten and the lens becomes flatter and refracts light less

Question 16

What is longsightedness and shortsightedness also called?

Answer 16

hyperopia and myopia

Question 17

What causes hyperopia?

Answer 17

Long sighted people the light is focused beyond the retina as its not refracted enough so close objects becomme blurry
and is as a result of a short eyeball or the lens just becomes to thin

Question 18

what causes myopia?

Answer 18

in people with myopia the light is focused ahead of the retina so far objects appear blured
and this could be from a lens that is too curved or a long eyeball

Question 19

how can you treat myopia or hyperopia?

Answer 19

use glasses with a concave (My) /convex (Hy) lens
laser eye surgery which can reduce the thickness or change the curve of the cornea
lens replacement can involve adding another permanent lens inside the eye or replacing the orginal with an artificial one

Question 20

how can laser eye surgery treat myopia and hperopia?

Answer 20

MYOPIA:
reduces the thickness of the cornea so that it can refract light less strongly

HYPEROPIA:
changes the curve of the cornea so it refracts light more effectively (strongly)

Question 21

whats the difference between hard and soft contact lenses?

Answer 21

hard contact lenses are made of rigid material and last a long time but need to be removed overnight to be kept sterile and prevent infection

sot contact lenses are made of flexible material that are comfortbale but dont last very long