Part of its function is to supply the rods and cones with nutrients and pump out their waste products. In the early stages of 'dry' AMD, this process slows down and whitish-yellow deposits of waste products start to accumulate.

The deposits are called drusen. Small drusen are relatively normal and most people will have at least one by the time they are 50 years old. However, if large amounts of waste products build up, the pigmented layer starts to die and the removal of waste products becomes even slower. The light-sensitive rods and cones cannot survive without the maintenance provided by the RPE and, in time, the macula starts to degenerate.

This type of macular degeneration usually progresses slowly over several years. Both eyes can be affected, although symptoms may develop in one eye long before the other. We do not know why the pigmented cells lose the ability to process waste. At the moment, there is no known treatment for 'dry' macular degeneration.