the human eye

light enters through

an opening

the human eye is similar to a camera as it focuses

light through a lens

eyes/cameras form a

Small, inverted image on a light-sensitive surface at the bak

the cornea is the

transparent outer layer of eye

what does the cornea do

refract light to pupil

The pupil is a

Black home in the iris

The __ is where light enters the eye

pupil

the pupil allows light to pass through to the

lens

the iris is a circular band of

muscle and colour

the __ controls the size of the pupil

Iris

the pupil ___ in a dim room

dialates

the pupil __ when there is a lot of light

contracts

the iris controls the amount of

light entering the eye

what are ciliary muscles

muscle fibres from sclera to lens

the ciliary muscle controls the

shape of lens & allows focusing

the lens is a

transparent, flexible, crystalline convex behind pupil

the lens

refracts/focuses light

lens is made of

proteins (higher concentration in body 60%)

when do the lenses in your eye thicken

as you grow older

lens loses ___ and the muscles surrounding the lens weaken

elasticity

sclera is the

white, dense outer layer of eyeball

the sclera helps with attaching

eye muscle

the sclera and vitreous humour maintains

eye shape

the sclera keeps the inside of an eye

dark

the vitreous humour is

transparent fluid cell that makes up most of the eye

vitreous humour allows light to pass from

lens to retina

the retina is an inner lining of

light-sensitive cells and nerves

the retina detects light and

sends a signal to optic nerve

photo receptive cells are called

rods or cones

rods are more sensitive to light and __

produce details

Cone cells detect

wavelengths of light (tgo)

the optic nerve is

a bundle of nerves from the retina at the back of the eye

the optic nerve creates a

blind spot (no light-sensitive cells)

the optic nerve transmits signals to the ___ for image processing

occipital love in the brain

An accommodation is the ability to

change the focus between objects at different distances by changing the curvature of the lens

When the ciliary muscles relax, the lens is stretched so ___ happens

less refraction

when ciliary musices relax it allows us to see

far

when ciliary muscles contract, the lens thickens causing ___

more refraction

when ciliary muscles contract, we can see objects

that are nearby

our eyes focus differently from cameras which

just need to move forward/backward

what is myopia

near-sightedness (cant see far)

what is hyperopia

farsightedness (can’t see nearby)

normal vision is when light is directed

directly on the retina

myopia is when light is focused

in front of the lens

People with myopia can focus light rays from

nearby objects

people who have ___ can focus light close up but not far objects

myopia

hyperopia is when light is focused

behind the retina

people with hyperopia can see

far objects clearly but not nearby

presbyopia is a form of

far-sightedness

presbyopia is when its harder to read print

as you get older since eye loses elasticity

astigmatism is when

eye doesn’t focus light evenly on the retina

astigmatism results in

distorted/blurred vision at any distance

nigjt vision in cats is enhanced by

tapetum lucidum (behind retina)

when we see cats eye in a picture or in the dark

they appear green cause of the tapetum

rods respond to change in

light levels

80% of light receptors on humans are (rods/cones)

rod

96% of light receptors in cats eyes are rods allowing

faster vision

(rods/cones) refresh (rods/cones)

rods; cones

light enters through

an opening