eye refraction

Question 1

when does refraction occur?

Answer 1

refraction occurs when light passes from one medium to another

light rays pass from the air into a denser medium = the light will slow down

Question 2

what are the refractive mediums in the eye?

Answer 2

the cornea, aqueous humour, lens and vitreous humour

Question 3

what is accomodation?

Answer 3

focusing on objects at difference distances. It is achieved by changing the shape and curvature of the lens - enables organisms to see close or distant objects

Question 4

what is accomodation mediated by?

Answer 4

it is mediated through ciliary muscles which change the refractive power of the lens, changing the degree of bending of the light rays

Question 5

what does the ciliary body do to see distant objects?

Answer 5

relax- ciliary muscles are taut

lens becomes elongated

Question 6

what does the ciliary body to do see near objects?

Answer 6

contract towards the lens - ciliary muscles are slackened

lens becomes rounded