Waste disposal in the eye

Overview

Age-related macular degeneration (AMD) affects the macula – the central part of the light-sensitive layer of the eye (the retina). We use the macula for the sharp, direct vision we need for reading and driving.

AMD takes decades to develop. Deposits of fat and protein (called ‘drusen’) build-up slowly in the macula, as a result of everyday wear and tear to the cells that detect light. Eventually the drusen cause damage to the macula by blocking the flow of nutrients in and waste products out.

It’s normal for older people to have some of these deposits and science has known about them for more than a century. But we don’t know how they start forming, or why they are bigger and there are more of them in people with AMD.

Dr Lengyel and team have been trying to find out. They have studied samples of the retina from a group of older people. Some had AMD, some didn’t. The results were unexpected.

All of the samples contained a type of calcium known as HAP. It’s one of a group of minerals that’s found in cow’s milk and blood.

We already knew that HAP is common in the body – it makes up the hard part of teeth and bones – but it had never been seen in this part of the eye before. And the fatty deposits seem to form around tiny bits of HAP.

There’s still lots to understand about exactly how the deposits form and whether they’re important for AMD, but this is an important discovery that gives us a potential piece of the puzzle we didn’t know existed.