Lecture 1 Flashcards
The vitreous makes up how much of the ocular volume
75%
Is the vitreous considered a CT
Yes
Make up of the vitreous
- 99% water
- Collagen, type 2. AKA Vitrosin.
- GAGs, help keep spacing
- Hyaluronic acid (gel)
- Chrondroitin sulfate - A few cells, inorganic salts, and soluble proteins.
Another name for collagen
Vitrosin
Attachment of the vitreous to the back of the lens
Weigers adhesion/ligament is the attachment at the back of the lens in a circle. Creates eggers line on the posterior capsule.
Directly behind the lens, in front of the vitreous, is bergers space
Strong to weak attachemnts
- Vitreous base
- Posterior lens
- Optic disc
- Macula
- Vessels
The vitreous is __x as viscous as water
4
Combination of which 2 things causes elasticity in the vitreous
Collagen and Hyaluronic acid
Vitreous liquefaction/synchysis seniles occurs when what happens ?
Hyaluronic acid depolymerizes- less gel, more water (lacunae) uneven spacing between collage – > aggregation makes visible bundles of fibers
Begins in the center.
Vitreous liquefaction/synchysis seniles before age 50 and after age 80. How much liquid?
Before age 50, 25% liquid
After age 80, 62% liquid
Syneresis
Shrinkage of the vitreous as solids and liquids separate
Fibriliary degeneration
Liquefaction and syneresis
Vitreous condensation
collagen fibers are drawn together
Essention phenom of coloquets
Dynamic. Have pt look up and then down. Can see it moving due to liquefaction.
Liquefaction starts earlier in what type of patients
Myopes and those with thin retinas
PVD commonly occurs in what age and gender
Females older than 45
Causes of PVD
Age
High myopia
Trauma
Inflammation - speeds up fibrillation process
Aphakia - no more anterior attachment to lens
Cataract surgery
Vitreoretinal degeneration
How to differentiate complete and incomplete PVD
Complete- presence of weiss ring
Tobacco dust/Schafers sign
RPE pigment due to liquefied vitreous disrupting bonds. Know there was a retinal break. Should not occur with PVD unless there is a break Always document (-) in chart
When present, 52x more likely to have retinal break
Complications of PVD
- VMT–> Edema –> Hole
- Vitreous hemorrhage
- If a PVD causes a vitreous hemorrhage, there is 75% chance it also caused a retinal break - Retinal break
- Tobacco dust/shafers (when present, 52x more likely to have a retinal break)
- 1/3 of symptomatic retinal breaks progress to RD - Retinal hemorrhage
What causes flashes and how many people report this when they have a PVD?
Traction causes physical stimulation of the photoreceptors.
If a PVD causes a vitreous hemorrhage, there is 75% chance it also caused
a retinal break
___ of symptomatic retinal breaks progress to RD
1/3
f/u schedule
- No retinal break or heme?
- No break but mild vitreous heme or peripheral hemes are present
- No break but significant vitreous heme or tobacco dust present
- See back in 3 weeks, 3 months, 6 months
- Repeat in 1 week, 3 weeks, 3 months, 6 months
- Refer to retina
marfan syndrome ocular findings
ST subluxation Axial myopia Small k diameter Increased risk of retinal detachment Vit degen
Syndrome that has a mutation in the fibrillan genes
Marfans
Ehlers Danlos ocular findings
High myopia Micro K --> Glaucoma Angiod streaks Lattice (vitreoretinal degeneration) Ptosis Strab
Anterior vitreous detachment is usually due to?
Associated with what else?
How to manage?
- Trauma or lens dislocation.
- Associated with retinal break due to high degree of trauma
- Look for tears or dialysis. If no break, follow up in 1 year.
Asteroid hyalosis incidence in the pop?
What is it?
1%
Calcium, phosphorous, oxygen, and lipid suspensions- adherent to the vitreous framework. Suspended throughout the collagen fibrils.
Asteroid hyalosis differential
Synchysis Scintillans - cholesterol crystals. Occurs in severely blind eye.
Settles after movement, reflective, may cause pseudo hypopyon.
