AMD Flashcards
what is the major tissue effected by AMD?
RPE
What fi, ndings your pt must have in order to have dry AMD ?
RPE changes, drusen, geographic atrophy
remember, hard drusen alone is not indicative of AMD
nor increase the likelihood of CNVM (choroidal Neovascularization)
How do you define hard drusen ?
Drusen that are < 6m microns in diameter
they could be from a single RPE cell filed with lipid or
focal deposits of hyaline materials in Bruch’s membrane
How do you differentiate between hard and soft drusen?
hard drusen are more superficial and shiny, small and well demarcated vs. hard drusen are deeper, duller, larger puffy and boarder not distinct
what is the chances of dry AMD to progress ?
Mild AMD –> low risk, 7.1 % will progress in 5 years
Severe AMD –> high risk, 13-18% progress in 5 yr, which are seen wt bilateral soft drusen
what can be used as an indication of progression to wet AMD?
number and size of drusens
what is happening in the RPE changes?
- mottling or salt pepper appearance, darker and lighter spots are indicative of RPE changes.
- damaged RPE cells lose their pigment which is taken up by the healthy RPE cells –> the appearance of both hypo & hyper pigment background.
how do you differentiate hard and soft drusen from RPE changes?
RPE changes the amount of pigment is constantly changing –> gives it darker and lighter appearance
- in drusen we only have hypo pigmentation –> we see lighter spots wt regular RPE appearance
what is the most visually threatening of dry AMD?
Geographic atrophy esp. if closer to the macula
what is geographic atrophy ?
large confluent atrophy of the RPE –> to atrophy of overlaying PR’s thus retina in general–> can see underlying choroidal vasculature
what is the risk of geographic atrophy ?
CNVM ,
Any time we have a RPE defect, the tight junction that make up the blood retinal barrier is damaged and no longer prevent the blood from choroicapillaries getting into the retina
what is the treatment plan for pts with geographic atrophy?
Low vision therapy
what causes geographic atrophy ?
It is a result of adjacent RPE & PR cell death
will anti VGEF helps in the case of geographic atrophy ?
no
what causes education of vision in dry AMD?
Geographic atrophy accounts for 10% of blindness related to AMD ( = dry)
what is the pathology of AMD?
- ischemia of retina and RPE due to dec. perfusion
- Senescence of the RPE
- RPE cell apoptosis due to inflammation & immune response
- Genetic factors effecting RPE or PR
- Accumulation of defective microglial cells , which support neurons, and ensure their well-being
what is the most responsible iso-form for angiogenesis ?
VGEF - A
where does a net in wet AMD originate from ?
Choriocapillaries
is AMD unilateral or bilateral ?
there is a 43% chance of progression bilaterally but asymmetric
what % of reduction in VA is done by drusen and RPE changes?
RPE changes and drusen are not major causes of VA reduction, which is a good news for pt
but the major threat to vision comes from geographic atrophy and CNVM
Do all AMD bleeding look the same ?
No bleeding comes from 2 different layer , sub-retinal and sub-RPE.
bleeding is from the outer layer of the retina ( RPE, Choroid )
In AMD, blood starts to break through at the level of the RPE & depending on how much it breaks through & level of degradation of the RPE, is going to determine what its like to look like to us clinically
Does all the bleeding look the same on PDR?
In PDR the inner vascular supply ( CRA) is leaking. so
in PDR the vessels growing typically superficially btw the virtuous face and the face of the retina, therefore they will almost look alike
