Visual System Flashcards
Which layer of cornea has HIGH REGENERATIVE capaticy?
epitelium
The layer of cornea is Acellular, unorganized collagen fibers, and is barrier to infection
Bowmans membrane
Layer of cornea that binds water, and maintains corneal clarity
Stroma
Stroma has what type of fibers?
type 1 collagen
which layer of cornea contributes to it’s thickness?
Stroma
These corneal cells will increase thickness with age and are entothelial cells
Descemets membrane
This simple layer of cells pumps water out of the stroma
Endothelium
Function of cornea
major refractive function
Nearsightedness is called ______
and has focus point:
Myopia
in front of fovea
Correct for Mypoia with a ______lens
Diverging or concave lens (-)
Farsisightedness is called _____
and has focus point:
hyperopia
beyond
Correct for hyperopia with a ______lens
convex lens
A perfect vision eye is:
diffraction limited
Lasik patient will have ____ point spread function and_______ wave aberrations
larger
tighter
What are the three layer of the choroid
vessel layer–> choriocapillary layer–> Bruchs membrane
Three contact regions of ciliary body:
vitresous body, sclera, chamber
How does aquouse humor drain from anterior chamber?
via trabecular meshwork
Where is trabelcular meshwork located?
near the limbus
What is the anterior surface of eye made of? and how does it determine eye color?
vascular, loose CT
has melanocytes and the number and type will determine eye color
What makes up posterior surface of iris?
double layer of pigmented epi to absorb light
Where is the pupilary dialator located?
bwn vascular and pigmented layer of iris
What nerve system innervates pupillary dialator m?
Sympatheic
Myoepithelial cells make up:
dialator pupillae muscle
-RADIALLY arranged
Concentric smooth muscle bunds at inner aspect of iris make up:
sphincter pupillae m.
Innervation of sphincter pupillae
PNS vi oculomotor nerve
Aqueos humor is located:
anterior chamber
Anterior chamber located:
between lens and pupil
Anterior chamber is vascular/avascular
avascular
What part of eye is key for maintaining intraocular pressure?
anterior chamber
What is the order for aqueous flow?
ciliary processes–> posterior chamber–> anterior chamber–> trabecular meshwork–> Schlemms canal–> veins of sclera
If you have open angle but have glaucoma, what is cause?
Issues with reabsorption and developes slower over time
If you have closed angle of iris what kind of issues will you ahve?
acute and quick and very painful.
Clincal signs of glaucoma include: Pressure
Elevated pressure above 12-22 mmHG called tonometry
Clincal signs of glaucoma: with visual field
visual field defect and have a selective peripheral loss of sensitivity
Can an indiviual have normal vision and glaucoma?
yes, may have 20/20 but will have poor diagnostic field
Why does glaucoma get caught late in the game?
because by the time people come in for glaucoma, 60% of ganglion are lost
Cup to disc ration: what ratio is bad
higher cup to disc ratio is BAD
Network of collagen finbers through which fibers thorugh which fibers of optic nerve exit the eye and are altered in glaucoma
Lamina crbrosa
What is our secondary refractive structure in eye?
Lens
Lens is avascular/vascular
Situtation with organelles?
high or low ECM
avascular
no organelles
low ECM
What makes up body of lens
lens fibers with no organelles
What is the ECM that surrounds the lens
Capsule
makes up anterior surface of lens
epithelium
What connects lens to ciliary body?
zonule fibers
When lens is spherical it has weaker/same/stronger optical power
stronger
Lens gets thinner when focused on:
and the ciliary muscles are:
distant objects
relaxed
Lens gets thicker when focused on:
and the ciliary muscles are:
near objects
contracted
When ciliary muscles contract it puts tension on:
This will thin out/thicken/ no change on lens
zonule fibers
thickens
opacification of the lens as you age:
cataract
cataract loacted in center of lens
nuclear cataracts
cataract that affects the layer of lens surrounding nucleus
cortical cataract
cataract found in back outer layer of lens and develop rapidly
posterior cataract
Acellular with type 2 collagen and hyaluronic acid
Vitreous body
provides nutrients to eye, is transparent and avascular
vitreous body
Located in neural region of retina and is for high aquity
fovea
What happens to nueral elements in retina as we move anteriorly?
decline to single layer covering ciliary body
What seperates retina from vitreous humor?
Inner limiting membrane–keeps retina packed in
if you have a thick ganglion cell layer, where are you located in the eye?
more posteriorly and closer to fovea, decreaess as we move peripherally or anteriorly
What are two clues on location of histology of location, central or peripheral, of eye?
The Gang Cell layer is thicker towards fovea
You do not and inner retinal layer at the fovea
Photoreceptors(rods and cones)
a. Inner segments:
: organelles for protein synthesis and E production
long- Slender outer segments.. numerous except at fovea
→very light sensitve
a. Rods:
Cones:
conical outer segments w/ membrane discs. Less sensitive then rods and responsible for high acuity and color vision
light sensitive
rods
gives us high aquity
cones
conical outer segments w/ membrane discs. Less sensitive then rods and responsible for high acuity and color vision
cones
What corrects for eye aberrations
Adaptive optics
Foveal pit devos after a thickening of
retina
Site of incipient fovea is_______ all along
avascular
After birth the cones get
better packed
Simple, cuboidal melanin containing epithelium btwn neural retina and Bruchs membrane (BM)
Retinal pigmented epithelium
Provides outer blood-retinal-barrier
RPE
a. melanin absorbs scatterd light
b. Transports nutrients and ions btwn photoreceptors and choriocapilarris
c. Spatial buffering ofions in subretinal spaced.
RPE
RPE will do what to the all trans retinal
reiosmerize them
Responsible for outer segment renewal
RPE
RPE secretes _______ for maintence and structual integrity of retina
GF
outer seg phagocytosis occurs on________ schedule w/ peak of rod outer disc shedding at______ and peak of cone outer seg disc shedding at______
diurnal
dawn
dusk
Blood supply: all branches in retina are from
ophthalmic artery
70% via_____ artery system off the opthalmic→ anterior ciliary artery (cornea/ciliary body/iris) + Posterior ciliary artery (long—iris and ciliary body) (short—choroid)
ciliary
30% of eye via_______ artery system off the opthalmic→ central retinal artery→ inner retina
retinal
Fovea: blood from choroid thus short ciliary branches from _______
anterior ciliary artery`
inherited disocer of melanin biosynthesis—see absent or reduced melanin pigment in eye and skin and hair
1:17,000
Albinism
Oculocutaneous albinism (OCA)— inheritance is
autosomal recessive
a. OCA1A=
b. OCA11B =
no pigment anywhere
some d/t leaky mutation allowing residual enZ (tyrosinase)
= X-linked and have normal skin and hair
Ocular Albinism (OA)
Clinical symptoms of albinism
a. Iris transillumination
b. Macular translucency
c. Foveal hypoplasia
d. altered ipsi/contra impairs stero vision
: flat membrane disc w/ photosensiteve visual pigmentation (opsin; structual and fnxional)
b. Outer segmets:
: transort of pros to OS: 10 billion opsin mole/secon~myosin VIIa and Kinesin II are the motor neurosn that do this
c. Connecting cilium:
