Vision 2
Terms
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- Retinitus Pigmentosa
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Slow loss of peripheral vision
night blind to total blindness - Diabetic retinopathy
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Nerves cannot feed retina
Ischemia: blood vessls serving retina
Retina detaches from the back of the eyes - Opthamalogist
- MD specializing in disease and muscles of the eye
- Optomotrist
- Person who measures for glasses and visual acuity
- Optrician
- Makes and sells glasses
- Definition: Legally Blind
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20/200 with correction
20/20 with 20 degrees or less field vision - Rods
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periphery of eye
More plentiful
Black and white, low and dimmed vision/light - Cones
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Color and acquity
More plentiful in center of best vision
Broad day light - Cornea
- Clear part of eye
- Sclera
- White part of the eye
- Lens
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refractive medium
relaxes and contracts - Retina
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Converts to electrical enery
Light sensitive back of eye - Conjuctiva
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Mucus membranes
line socket and lids - Iris
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color part
open pupil to let more light in - Optic Nerve
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originates at retina
Goes to brain - Optic Disc
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all cells
Blind spot - Macula
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general area try to get image to focus on
Mostly cones
Area of good vision - Fovia
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Very center of macula
Not good for night vision
All cones centered here
Best vision in good light - Ciliary Body
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set of muscles that makes lens and iris open or close
contracts and releases lens and iris - Cataracts
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cloudiness/opacity of lens
all or partial replacement of lens needed
prosthesic impant
if partial cataract- may come back
seile cataract- with old age
result of trauma, surgical, heat, or system disease - presbyopia
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old vision
lens doesn't refract fully anymore
hardening of lens - astigmatism
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multi-focusing
irregular shaped lens or cornea - strabismus
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crossed eyes
muscular imbalance between eyes
Can be corrected surgically - Hyperopia
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Far sited
Focus behind retina
Distance is better - Myopia
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Near sited
Focus in front of retina - Emmetropia
- Proper vision with refraction
- Amblyopia
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lazy eye
patch is put on good eye to correct
brain confused and shuts down lazy eye - Nystagmus
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involuntary side to side movements of eye
spastic - Glaucoma
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#1 cause of blindness
pressure in eye due to not draining fluid
interoccular pressure
blocakge of canal of schlemm
Medications to open up- laser surgery
Problem: if not caught early -> blindness - Macular degeneration
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areas of no vision
eye creates an additional blind spot
macular holes- no central vision - parapetologist
- mobility instructor
- low vision specialist
- optomologist with specialization