Eye Flashcards
Define accommodation
Change shape of the lens to flow on near objects
What happens when ciliary muscle contracts
Suspensory loosen
=means lense is thicker+ refracts light rays more strongly
What happens when focusing on near objects
Ciliary muscle contracts
=suspensory ligaments loosen
=lens slack (loosen)
What’s long sighted called
Hyperopia
What’s long sight
Can’t focus on near objects
How to treat hyperopia
Glasses with convex lenses
= light rays bent more
= light rays focused on retina
What’s short sight called
Myopia
What happens when focusing of distant objects
- ciliary muscles relax
- suspensory ligaments contract
- lens becomes stretched
Why does a long sighted person have difficulty seeing near objects
How someone’s eye can adjust to form clear image of near object
- ciliary muscles contract
- suspensory ligaments loosen
= lens thickens
= thicker lens is more convergent
= light rays focused on retina
How to treat myopia
Glasses with a concave lens
= diverging lens
What happens to eye of short sighted
Image focuses before retina
What happens to eye of long sighted
Image focuses behind retina
How does eye see light
Retina is sensitive to light
Impulse pass along sensory neurone
Along to optic nerve
Describe myopia
Eye ball is too short
= light focuses behind retina
