Eye Flashcards
What causes cataracts?
Protein build up which causes clouding in the lens
How do we treat astigmatism?
Corrective lenses
What causes astigmatism
Inherited
Injury
What contains ciliary muscles?
The ciliary body
What is the function of the shape sort ligaments?
Controls the thickness of the lens
What are the suspensory ligaments attached to?
Lens
Pupil:
The hole in the eye that changes size due to the iris
What contains pain receptors?
The cornea
Where is the site of highest light refraction?
The cornea
What does the cornea cover?
The front area of the eye
What part is responsible for the pupillary mechanism?
The iris
Iris:
Radial and circular muscles
Which structure of the eye is responsible for how much light enters the eye?
Iris
The function of the lens is to:
Refract and focus light into the retina
What two characteristics about the lens allows it to do it’s function?
Flexible
Transparent
The function of the choroid is to:
Provide nutrients to the eye and absorb excessive light
Which layer of the eye is filled with blood vessels?
The choroid
Where is the blind spot created?
Where the optic nerve leaves the eye
Area of the retina where there are no rods or cones
Blind spot
Which area of the retina produces the highest focus?
Fovea (yellow spot)
What are rods for?
Black and white vision
What are cones for?
Colour vision
The receptors of the eye are the:
Rods and cones
Function of the sclera:
Protects and maintains the shape of the eye
Function of conjunctiva:
Protection
Sclera:
White, fibrous layer of the eye
Distant vision:
> 6m
Ciliary muscles contracts
Suspensory ligaments slacken
Lens becomes more convex
Refraction increases
Clear image formed on retina
Bright light:
Radial muscles relax
Circular muscles contract
Pupil reduces
Less light let into the eye
Dim light:
Radial muscles contract
Circular muscles relax
Pupils dilate
More light let into the eye
Cataracts:
Cause: old age where proteins in the eye clump together resulting in clouding of the lens where less light enters the eye
Treatment: surgery to remove hardened cloudy layer above eye
Astigmatism
Causes: hereditary but can be caused by injury; irregularly shapes lens or cornea
Treatment: corrective lenses
Hypermetropia
When you can see far away but not close up
Eye is too short
The cornea of the lens is too flat
Light rays meet behind the retina
Solution: wear convex lenses
Myopia:
Can see close but not far
Eyeball is too long
Cornea or lens is too convex
Light rays meet in front of the retina
Solution: wear concave lenses
What visual defect is when you can see close up but not far?
Myopia
What visual defect is when you can see far away but not close up?
Hypermetropia
