ARMD Referral - Is It Wet Or Dry?

Good guest lectures this week! Man yeah! This one was to refer/not to refer. Wet Vs Dry. There ain't no helping dry at this point. Wet can be helped by that lucentis thing that everyone reads about in the paper and gets all excited about. Lucentis inhibits VEGF-A which plays a critical role in the formation of new vessels which are responsible for the leakages.

Anyhoo, the RPE is critical in AMD. Drusen form in the RPE. Drusen are of course waste products of reactions in the retina that haven't been removed properly. They pile up in bulges. They have nothing to do with leaking blood vessels. In summary DRUSEN TAKE PLACE IN DRY AMD, ARE YELLOWISH, ROUND AND DEEP IN THE RETINA.

Stuff tagged as DRY

• Atrophic
• Drusen
• Geographic (kinda 'islands' of atrophy)
• RPE atrophy, changes

Stuff which is involved w/WET

• Exudative - stuff exudating out of blood vessels
  
• Disciform (round shaped fibrous scarring)
• Neovascular
• Choroidal Neovascular Membrane - network of all sorts of aberrant BV all over the place. More like a net/mesh

Exudates ain't drusen. They are higher up, hard edged and whiter. Another area of confusion is the Chorodial Neovasc Membrane. This membrane can either be

• Occult - hidden beneath the RPE so nothing visible to zap with PDT
• Classic - membrane has broken through the RPE and is visible

These days now lucentis is the main treatment that's replaced the laser so whether the membrane is occult or classic doesn't matter as much.

Various Things - To Refer Or Not

Oedema

• There are lots of causes of swelling at the macula, central serous retinopathy, cystoid macular oedema etc
• It's difficult to distinguish
• Which layer of the retina is raised?
• Try to avoid using oedema as a primary indicator of wet AMD

Amsler Chart - Distortions

• Distortion is a good indicator, but when the px mentions it before the amsler as opposed to when you're testing for it - the amsler is a very sensitive test. Drusen can raise the macula a bit causing a bit of distortion, as do PED and central serous retinop. In fact any macular disease can cause distortion.
• If the px is reading 6/9 N6 or better then they are highly unlikely to have treatable macular disease. No referral in that case, monitor!

Drusen

• Can be soft/hard
• More a risk factor for ARMD

Blood

• Shouldn't be any visible - leakage if there is - aberrant vessels
• Different from the background diabetic spots

Exudate

• Not good - indicates leaking aberrant vessels
• Could be present with or without visible blood
• Exudate is not treated directly, it's just a sign of potentially treatable new vessels

Exudates/Blood, refer!