Flashcards in BCSC Retina Deck (544)
What is the ligament of Wieger?
A condensation of collagenous fibers attached to the posterior lens capsule.
How wide is the vitreous base?
2mm anterior and 3mm posterior to the ora serrate.
Where does the vitreous attach?
The vitreous base, lens capsule, retinal vessels, optic nerve and macula.
What is the vitreous made of?
Collagen fibrils separated by hydrated hyaluronan molecules.
What is the area of Martegiani?
The attachment of the vitreous to the disc.
Where is the macula clinically and how large is it?
The area between the disc and temporal vascular arcades, it is 5.5mm.
What defines the macula histologically?
The area with 2 or more layers of ganglion cells.
Why is the macula yellow?
Due to the accumulation of carotenoids, especially zeaxanthin and lutein.
What defines the fovea?
1.5mm area where the only photoreceptors are cones.
What defines the foveola?
0.35mm in diameter, where the INL and ganglion cell layer are displaced laterally.
What is the umbo?
150 micrometers in diameter, the central depression of the foveola, where cones are elongated.
What is the parafovea?
0.5mm ring around the fovea where ganglion cell layer, INL and OPL are thickest.
What is the perifovea?
1.5mm wide area around the parafovea.
What is the ora serrata?
The border between the retina and the pars plana.
Where do most retinal tears occur?
At the posterior border of the vitreous base, between the ora serrata and the equator.
What is a dentate process?
Jetties of retinal tissue extending anteriorly towards the pars plana.
What are ora bays?
Posterior extensions of the pars plana towards the retinal side.
What are meridonal folds?
Radially oriented thickening of retinal tissue extending to the pars plana,
What are the layers of the retina?
1. Inner limiting membrane 2. nerve fiber layer 3. ganglion cell layer 4. inner plexiform layer 5. inner nuclear layer 6. middle limiting membrane 7. outer plexiform layer 8. outer nuclear layer 9. external limiting membrane 10. rod and cone inner and outer segments
Where are rods the most dense?
20 degrees from fixation.
How many cones does one midget bipolar cell synapse with?
Do bipolar cells synapse with one or many rods?
What do amacrine cells do?
Help in signal processing by responding to changes in retinal stimuli like change in light intensity.
What is the ILM (internal limiting membrane)?
The foot pads of Muller cells, which attaches to the posterior cortical gel of the vitreous.
What is the XLM (external limiting membrane)?
Zonal attachments between photoreceptors and Muller cells, can be seen on OCT but not true membrane.
What supplies the inner retina?
The central retinal artery.
What supplies the outer retina?
What is the RPE?
Pigmented cells from the outer layer of the optic cup, continuous with pigmented epithelium of the ciliary body and iris.
Where is the apex of the RPE cell?
Facing photoreceptors, enveloping the outer segments.