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16 Cards in this Set

  • Front
  • Back
layers of the eye
outer sclera; cornea as anterior 1/6
middle choroid/uvea- vascular and pigmented; forms ciliary body and iris stroma anteriorly
inner retina
vitreous vs aquaeous humor
vitreous- gelatinous with phagocytes; behind lens
aqueous humor- prod in posterior chamber( b/w iris and lens) by ciliary body; imp for intraocular pressure (glaucoma); drains through canal of schlem
what is the first layer of the eye to focus light?
cornea
what is the output of the retina?
retinal ganglion cells; their axons form CN II
what wraps around CN II?
meningeal layer with CSF
build up of CSF-> compression of CNII -> damage/elevation of optic disc and retinal hemorrhage (papilledema)
what happens to light as it passes through the lens?
it forms an inverted, reversed image on the retina
what are the 2 focusing elements of the eye? which is the most powerful?
cornea (2X as powerful) and lens
what shape is the lens? what does this do?
convex; focuses light on the focal pt
(distance from lens to focal pt = focal length)
how does focal length change with the shape of the lens?
flatter lens-> longer focal length
more convex-> decr FL
what is a diopter?
describes power of the lens
D= 1/FL
what is myopia?
nearsighted-light focuses too close (thick cornea or long eyeball)
use concave lens to adjust (incr FL)
what is hyperopia?
farsighted -light focuses too far away
(thin cornea or short eyeball)
use convex lens to shorten FL
accomodation
lens bulges with close vision in order to have enough refractive power to focus the image
distance vision- flat lens; taught zonule fibers and relxed ciliary mm.
close vision- fat lens; loose zonule fibers, contracted ciliary m.
what is presbyopia?
loss of ability of lens to accomodate with age
due to loss of elasticity of lens
what is a method by which we incr resolution of an image?
reduce size of pupil
(PSNS innervates sphincter of iris)

(side note: SNS innervates dilator m. of iris)
what 3 things happen when we accomodate?
"near relfex"
pupil constricts
eyes converge
eyes accomodate
all via CN III and Edinger Westphal nucleus