L3Notes - Ciliary body: circular muscle, contracts to a...

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3 cones, long medium short, blue yellow red colorblind: miss one kind of cone light: left right large distance: 20 ft laser: light in a straight line ways to bend light: water, magnifying it emmetropeia: perfect eye focusing (tear film, cornea, crystalline lens: key in bending light) macula: dense photoreceptors, for reading *at what distance are things out of focus?—key question for diagnosis 20/40 (ft): test distance/letter size Myopia: light approaches parallel, but light focuses in front of retina the higher contrast, the easier to see/read recognizing a face, seeing stair step: low contrast task 0.33mm too long 20/40 most children are born farsighted 3 theories for myopia development: see myopia development slide #12 parental history is more predictive than near work reports concave lens diverges light to focus myopic eyes relative curve inside curves more than outside curve Hyperopia: Not total opposite of myopia Why don’t farsighted ppl need glasses? Zonules: similar to fishing wire, clear + stringy, *suspend crystalline lens
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Unformatted text preview: Ciliary body: circular muscle, contracts to a smaller circle Do more work to focus near Convex lens converges light Presbyopia: Eye’s ability to focus decreases w/ age Taller ppl need reading glasses later than short ppl, arm length More cells, more rings on crystalline lens, less accommodation Cataract: Can’t see by looking at eye Anything in crystalline lens that’s not perfectly clear Removed by vacuum Makes them presbyope No-line bifocal Gradual change in lens prescription from distance to near Astigmatism: Cornea not spherical 3 #’s: 1 st , distance, 2 nd , astigmatism, 3 rd direction of astigmatism smears vision so you can only read 3 or 4 letters from each line most genetically predictable: autosomal dominant RK how long, how deep, how many can correct nearsightedness, not farsightedness PRK Laser on eye Scrape off epithelial tissue before reshaping Became more hyperopic LASIK Similar to PRK, but cut flap instead Bowman’s layer?...
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This note was uploaded on 09/24/2009 for the course OPTOM c10 taught by Professor Levi during the Spring '08 term at Berkeley.

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L3Notes - Ciliary body: circular muscle, contracts to a...

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