eye physio Flashcards
exam 2
what is the structure that gives color to the eye?
iris
anterior chamber filled with
aqueous humor
posterior chamber filled with
vitreous humor
Lens: ____ of focusing power
1/3
is the image inverted when looking at an object?
yassss
light from fixation point falls on
fovea (high acuity)
cones allow for
color
daytime
low light sensitivity
rods allow for
black and white
high light sensitivity
do cones have different areas of color spectrum absorbance?
yasss
Blue at 420
green at 534
red at 564
are there more rods than cones?
where are they distributed?
more rods than cones but the rods are located in the periphery vs cones located in the fovea
macula has a yellow pigmetn?
yass
nerve fibers from the temporal retina remain
ipsilateral
damage to optic nerve
loss of vision in one eye
damage to optic track
loss of half visual space- hemianopoia
Nerve fibers from the retina then proceed to the ________ nucleus of the thalamus where they synapse
Latergenicualte nucleus
fibers from the nasal retinas
cross over in the optic chiasm to from the optic tract
Fibers carrying information about the upper visual space sweep further out into the temporal lobe _______ and then proceed to the ________ ventral to the calcarine fissure
(meyer’s loop) and then proceed to the lingual gyrus
While fibers carrying information from the lower visual space run ______ and synapse _____ to the calcarine fissure
more medially and synapse dorsal
Convergence _______ as one moves away from the fovea by enhancing the sensitivity at the expense of spatial resolution
increases
- by enhancing the sensitivity at the expense of spatial resolution
rhodopsin activation involves retinal isomerization
what happens?
11-cis-retinal to 11-trans-retinal
age related macular degeneration (MAD)
Symptoms
- Early stage:
- Middle stage:
- Later stages:
Symptoms
- Early stage: No symptoms
- Middle stage:
- –>Blurred central vision. Often objects look distorted and dim, and colors look faded.
- –>Straight lines may appear distorted and wavy
- –>A blurred or dark spot in the center of vision gradually gets larger and darker.
- Later stages:
- –>The patient may not be able to recognize faces until they are close
—>typically does not affect side (peripheral) vision.
what is the progression of MAD?
Dry or wet
retinitis pigmentosa caused by
- genetic inheritance: AD, AR or X-linked
2. mutation in Rhosopsin- most common mutation is to the beta subunit of cGMP phosphodiesterase/ PDF
what are the symptoms of retinitis pigmentosa
- Decreased vision at night or in low light, usually starts in childhood.
- Loss of side (peripheral) vision, causing “tunnel vision”.
- Loss of central vision in advanced cases.
sign of retinitis pigmentosa?
black bone-spicule pigmentation
the two stages of diabetic retinopathy?
- non-proliferative
2. proliferative
cotton wool spots
diabetic retinopathy
build up of pressure in the eye leads to daamage of the optic nerve head
glaucoma
types of glaucoma
- open angle
- closed angle
- congenital: improper development of trabecular network
