Vision I-II Flashcards
name the major structures that light passes through before reaching the retina
cornea, anterior chamber, lens, vitreous body
important structure in the eye for color vision
fovea of macula
how is the light signal sent to the brain?
once light hits retina, it initiates a biochemical series of events in photoreceptors, which are sent to the brain via the optic nerve
what produces aqueous humor? b lockage of aqueous flow causes what disease?
ciliary body
glaucoma
the path of aqueous humor
produced by ciliary body, flows from posterior chamber to anterior chamber and to the Canal of Schlemm
in glaucoma, which part of the visual field is impaired?
peripheral vision
the meninges around the eye from outermost to innermost
sclera (dura), choroid (pia + arachnoid), trabecular meshwork, granulation (arachnoid)
what happens if there is a blockage of the arachnoid granulation?
open/wide-angle glaucoma
what is accommodation?
changing the curvature of the lens to bring an image to focus on the retina
is the lens fatter or thinner when looking at something close?
fatter
name the muscle that helps to change lens curvature?
ciliary body
name the ligament that helps to change lens curvature?
zonule of Zinn
name a disease condition when a person has trouble focusing on an object because of a lens problem
astigmatism
farsightedness due to the lens losing elasticity during the aging process
presbyopia
what type of lens corrects for presbyopia?
convex
occurs when the lens loses opacity
cataract
difference in vision of px with glaucoma vs cataract
cataract makes whole visual field blurry, not just periphery like glaucoma does
is myopia determined by genetics or can it be caused by the environment?
mainly genetic but may also have environmental factor role
name for normal eye; name for when eyeball is to short; name for when eyeball is too long
emmetropia; hyperopia; myopia
eyesight problem caused by curvature of the cornea or the lens
astigmatism
can a person have myopia with astigmatism?
yes
layer of the retina where the photoreceptor cell bodies are
external nucleus layer
cells in this layer of the retina play important roles in relay/modulation of signals
internal nucleus layer
axons of these cells become the optic nerve
ganglion cell layer (of the retina)
order of layers of the retina from outermost to innermost
external nucleus layer, internal nucleus layer, ganglion cell layer
4 major cell types in the internal nuclear layer
Muller supporting cell (major glia), horizontal cell, bipolar neuron, amacrine cell
these cells in the internal nuclear layer modulate signals sent out by photoreceptors
horizontal cell
these cells in the internal nuclear layer relay signals between the cell layers
bipolar neuron
these cells of the internal nuclear layer modulate function of ganglion cells
amacrine cell
what is the optic nerve composed of?
axons from ganglion cells collected into a bundle become the optic nerve
*the area where the ganglion cell axons exit the eyeball
papilla (optic disc)
why is the fovea of the macula an area with high visual acuity?
it has high number of ganglion cells and cones
what is the optic disc a collection of?
ganglion cells ready to leave the eyeball; no photoreceptors, so no image happens when light falls onto this spot (blind spot)
where is the macula of the eye?
lateral to the optic disc in an avascular area
why is the macula in a region with no blood vessels?
helps macula acquire its high visual acuity because light is not blocked by blood vessels
what is the center of the macula? what is found here?
fovea. cone photoreceptors
the landmark used to define the various parts of the retina; the various parts?
the macula
superior retina, inferior retina, nasal retina, temporal retina
a disease that affects the macula
diabetes; Stargardt disease
leading cause of blindness in the elderly
macular degeneration
what part of the visual field is lost in patients with macular degeneration?
central vision
which layer of retina cells is affected by macular degeneration?
ganglion cell layer
causes of abnormal appearance of the optic disc
when ICP is high, CSF presses on the optic nerve
high ICP can cause abnormal optic disc appearance known as…/ what are possible causes of high ICP?
papilledema (distorted blood vessels, optic disc loses its fine edges and swells)
hematoma, hydrocephalus, brain bleeds