Eye Flashcards
Focal point
A place where light rays meet after refraction
Your sight
Relies on light entering the eye from the environment and being collected by the light sensitive receptor
What do light rays do?
Reflect off everything you see
Sclera
Tough white outer layer, front
Cornea
The layer of fluid, on the top of the eye
Iris
The coloured part of the eye
Suspensory ligaments
Hold the lens
Ciliary muscles
Pull on the sensory ligaments, move the lens
Retina
The light sensitive part of the eye, contains lots of receptors
Optic nerve
Send electrical impulses to the brain
Blind spot
Only place where it doesn’t contain any retina cells
Lens
Focuses the light that enters the eye to give clear vision.
Near objects- ciliary muscles
Contract
Suspensory ligaments- near objects
Loosen
Near objects- Lens
Gets thicker and refracts more strongly
Ciliary muscles- distant objects
Muscle relaxes
Suspensory ligaments- distant objects
Ligaments tighten
Lens- distant objects
Lens pulls thin and refracts only slightly
Short sighted
People’s near vision is usually clear, they should have a concaved lens.
Long sighted
Light that comes into your eye is focused behind the retina rather than on it- eyes have to work hard to re-focus, therefore needing a comvexed lens
Short sighted Symptoms
Objects in the distance are blurred, close objects are usually clear, headaches, eyestrain
Long sighted symptoms
Blurred vision when looking in the distance, especially when looking at close objects, headaches
Convexed lens
Help people see further away and makes the light converge before the retina- without the lens the light would converge before the retina.
Lasik laser eye surgery
done with two lasers, one to open up a flap in the cornea, it is removed so the surgeon can reshape your cornea-
