The macula is the central part of the retina and it is the part that we use to look at things in detail. When something starts to go wrong with the macula, our detailed vision develops problems.
Macular Degeneration comes in two types. Dry, where the base layer of the retina becomes lumpy and consequently distorts the image falling on it. And wet, where there are leaks from the tiny vessels within the retina causing damage to the retinal nerve cells.
The dry type can be associated with nutrition, so if you suffer from it in one eye you will often be advised to take a supplement of ocular nutrients to try and prevent it degenerating more.
The wet type has shown itself to be amenable to being treated with drugs, which have to be delivered very close to the retina indeed. It is only since the advent of the OCT scanner that it has been possible to monitor Wet Macular Degeneration.
There are other causes of macular change, such as diabetic maculopathy and Central Serous Retinopathy, which have different causes and may or may not be treatable in the same way as Wet Macular Degeneration.