What is the retina?
sensory mem, lines inner back of eyeball
What is the function of the retina
Contains photoreceptors that convert light signals into nerve impulses to be interpreted by brain - photransduction
Structure and func of fovea
Centre of macula
Avascular
Only cones- no blue ones
Responsible for central vision
density of cones = high VA
foveal reflex= bright pinpoint of light
Why is there a red reflex?
light reflected back from choroidal bld vessels
Opacities mean: cataract/corneal clouding OR retinal detachment
Structure of fovea pit
Ret thinner
No blood vessels
VA improves as fovea develops
Name the layers of retina
CHOROID
RPE
Photorecep
Outer limiting mem
outer nuclear layer
outer plexiform layer
inner nuclear layer
inner plexi
gang cell layer
NFL
inner limiting mem
VITREOUS
My Nerves Get In Knots Outside Our Easy Practice Review ( from vitreous to choroid)
function of ora serrata
seperate junction btwn choroid and ciliary body
Structure and function of RPE
transfer waste and nutrients btwn ret and choroid
phagocytosis of photoreceptors
Absorbs stray light
hex cells; tight junc;control mvt of sub
cells not replaced
Types of photreceptors.
Function of each cell in neurosensory retina
Bld supply in retina
2/3 from CRA
1/3 from choroid
X alternative bld supply ; oclussion risk
more demand centrally; more cones
end arteries
What is the cilioret artery
Extra bld vessel
20% pop
from PCA
How does colour vision happen
Blue cones= S wavelength
Green cones= M wavelength
Red cones= L wavelength
if any missing= clour vision defect
Tools to view retina
Opthalmoscope - smallest FOV (8 degrees)
Volk
Fundus camera- largest FOV
OCT- 45degrees
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