review of eye anat and phys

Question 1

what causes corneal swelling

Answer 1

decrease 02 from atmosphere due to contacts

Question 2

why is cornea transparent

Answer 2

ideal collagen arrangement and avascular (soluble VEGFRs)

Question 3

define diopter: how far would an image focus thru lens of 60 diopters

Answer 3

1/focal length in meters. 17mm or 1/60 of a meter

Question 4

why is lens clear

Answer 4

extra long fiber cells lose organelles

Question 5

where is aqueous humor produced and how

Answer 5

ciliary epithelium (two layers). driven by na/k pump.

Question 6

intraocular pressure equation

Answer 6

IOP=(Fin-U)c+PE

PE=episcleral venous pressure

Question 7

ways to lower AH production

Answer 7

timolol, acetazolamide (CA inhbitor)

Question 8

why do glaucomas mostly affect optic nerve head and consequences

Answer 8

the lamina cribrosa is the most fragile part of eye. compresses axons, disrupting transport and blood flow resuling in ganglion cell loss

Question 9

retinal circulation: control? where?

Answer 9

metabolic, not autonomic. inner retina only

Question 10

choroidal circ: control? flow rate?

Answer 10

autonomic, no metabolic. much higher than retinal flow

Question 11

what layer of retina is avascular

Answer 11

outer layer (photoreceptors). why retinal detachment from choroid is bad

Question 12

main pathway for ligth transduction

Answer 12

photoreceptor to bipolar to gnaglion

Question 13

fxn of Retinal pigmented epithelium

Answer 13

light absorption, nutrients, glia, visual cycle (regeneration of opsin),

Question 14

why is acuity so much higher in fovea

Answer 14

more ganglion cells per unit area(not actually in fovea but right around), less convergence(2:1 ganglion:cone b/c of on and off gnaglions)