🟣The Eye Flashcards
Cornea
Transparent part at front of the sclera
Iris
Coloured part of eye
Controls pupil size
Pupil
Hole which light enters through
Lens
Clear disc
Changes light ray direction to fixes them
Ciliary muscle
Changes lens shape by contractions / relaxing
Suspensory ligaments
Attach lens to ciliary muscle
Sclera
White outer layer of the eye
Don’t forget these (definition not needed)
Retina
Optic nerve
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What do the eyes do to look at a distant object?
Ciliary muscles contract
Suspensory ligaments loosen
Lens = thick + refracts light rays strongly
What do the eyes do to look at a close object?
Ciliary muscles loosen
Suspensory ligaments contract
Lens = thin + refracts light rays less
What’s myopia + causes
Short sightedness
Close objects clear but distant objects = blurry
Light rays meet too early (before retina)
Lens too thick / eyeball too long
How to fix myopia
Concave lens
Spreads out light rays more so they focus on the retina
What’s hyperopia + causes
Long sightedness
Close objects = blurry but distant objects = clear
Light rays don’t meet before retina
Lens too thin / eyeball too short
How to fix hyperopia
Convex lens
Refracts rays inwards so they focus on the retina
Ways to correct myopia / hyperopia
Myopia = concave lens
Hyperopia = convex lens
Soft / hard contact lenses
Laser surgeries = change cornea shape
Replacement lens in the eye
