Drusen and the "Eye Poop" Exchange
Years ago I was told I had drusen. I had no idea what they were then. Turns out many if not most people of a “certain age” have drusen. They are not in-and-of-themselves a sure sign of age-related macular degeneration. The “rule” sounds like one of those logic puzzles: not all people with drusen have AMD but all people with AMD have drusen. Got that?
What are drusen?
My spelling and grammar check on my tablet capitalizes drusen every time I type it. That is because it is a German noun and all German nouns get capitalized. At least in German. Drusen is also a plural noun. Singular is druse, but no one probably ever has one druse. The things travel in packs.
Drusen are politely described as deposits of extracellular waste or as deposits of fatty, metabolic waste. That, to me, is eye poop.
What do RPE cells do?
Earlier we talked about the retinal pigment epithelial cells. The RPEs have as one of their jobs ingesting the fatty metabolic wastes from the photoreceptors. Translated, they eat eye poop. Yuck.
There is no answer to why RPEs stop eating eye poop. Probably just get really tired of a seriously crappy and limited selection for dinner. Anyway, they stop eating and the eye poop builds up and up and up.
Types of drusen
As I said, nearly everyone of a certain age, read 60, has had RPEs stop eating and has developed piles of eye poop as a result. As a rule of thumb, the little, hard drusen are harmless. It is the big, fat, squishy ones you have to look out for. As your ophthalmologist is looking in your eyes and dictating he will call the big, fat, squishy ones “soft”. That is when you pay attention. Soft drusen mean trouble.
What does the Bruch's membrane do?
Drusen create a nasty working environment for the cells in your eye but this is not all they do. They also creep in between the RPEs and the Bruch’s membrane. Think of the Bruch’s membrane as the store as well as the garbage transfer station. The healthy RPEs go to the Bruch’s membrane for supplies. They also take the trash there and throw it in the dumpster to be taken away.
What do drusen do?
Now imagine there is a big pile of eye poop that has gotten between the RPEs and the Bruch’s membrane. With no way to get supplies and no way to get rid of the trash, the RPEs are doomed. And remember, if the servants are doomed, so are the potentates. The photoreceptors will die as well. And there, my dears goes our central vision.
There are things in the works to try to interfere with this process. When they tell you dry AMD has no treatment and no cure, mentally add the word “yet” to the statement. One of the things they have been looking at is interfering with the vision cycle. The thought is, if they can slow down the metabolic process of the photoreceptors, they can reduce the eye poop and make life easier for the RPEs.
Interesting theory but all I can think of related to that is low waste dog food they used to advertise. I was leery of that. Did not want constipated pups. Can photoreceptors get constipated? Things that make you go "hmmmmmm?"
My vision loss
That is pretty much what I found out researching after I “lost” my central vision in my first eye. I had been assured it would be a long time until I “lost” my second eye and REALLY had to worry. Yeah, right…
Next stop will be January 2016. See you there.
Have you visited our new sister site, ChronicDryEye.net?