Three Types of Wet AMD

Well, the kitchen floor is now mopped. Took a deep breath and went back into the housekeeping fray after that last page. How do people get motivated for that sort of thing every day?

With a nod to our ‘wet’ readers, I am going to tackle an article on how to image different types of neovascularization. Not sure I am going to get very far because I never even ‘knew’ there were different types of choroidal neovascularization.

First off, to the article talking about imaging retinal angiomatous proliferation. Huh? Back to EyeWiki.

Choroidal neovascularization starts in the choroid. It erodes through the RPEs and results in chorioretinal anastomosis. Anastomosis? Lovely. Anastomosis is the connection of two vessels that were not previously connected. Sort of like a shunt. Got it? Good; moving on.

Retinal angiomatous proliferation is a process that happens ‘backwards’. It starts in the retina and progresses into the subretinal areas. It eventually connects the retina and choroid by forming an anastomosis. That is a connection where there is not supposed to be one. See previous paragraph.

Retinal angiogenesis proliferation has been called type 3 neovascularization. This begs the question: what are types 1 and 2? Type 3 is rare with 10% to 20% of people with wet AMD having this type of disease. This may be a good thing because the article lists all sorts of complications that are common in type 3 but rare in the other two types.

So now I have to do a little more digging and find neovascularization types 1 and 2. Back to EyeWiki where I discovered this: In type 1 the new veins are below the RPE layer. In type 2 the neovascularization passes through the RPE layer and compromises the neurosensory retina. That means it gets far enough to directly mess with the photoreceptors. Type 1 is hidden and type 2 is classic.

As far as treatment is concerned, ResearchGate.net (7/15) suggests type 1 can be treatment resistant. My guess – please note this is a guess – would be this is because type 1 is ‘buried’ in lower regions of the eye and anti-VEGF may have a harder time getting to it. That buried nature of type 1 – and another article – makes me think what we are talking about here is the occult type. Saw that classification before. Just needed to make the connection. Dawn does occasionally breaks over Marblehead.

Anyway, anti-VEGF treatments are still first choice although I am starting to see references to photodynamic therapy (“cold laser”) and even surgery. Maybe we should look into that, too.

Type 2 is the classic type. My reading suggests ‘shots’ are the treatment of choice there.

And as far as type 3 is concerned, it appears that in spite of the complications reported, type 3 can be treated rather successfully. Anti-VEGF injections do the trick, sometimes even on the first try.

So there you are the three types of wet AMD. Learn something new everyday.

written October 24th, 2017

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