CHECK-UP:The exact cause of age-related macular degeneration (AMD) is not known, writes MARION KERR
CAN YOU tell me what age-related macular degeneration is?
The macula is a small area located in the retina at the back of the eye. It allows the eye to see fine details clearly and the vision necessary for a range ofactivities such as reading or driving. When the macula is not functioning it can cause central vision to be distorted, resulting in areas of darkness, distortion or blurring. Macular degeneration affects central vision but does not alter peripheral vision. Some older people develop macular degeneration as part of the natural ageing process. This is known as age-related macular degeneration (AMD). The exact cause is not known.
I’ve heard macular degeneration can be either wet or dry. What’s the difference between the two forms of the condition?
The dry form affects most people with the condition. It causes gradual visual loss and is the result of a thinning of the tissues in the macula. The wet form of macular degeneration accounts for about 10 per cent of all AMD cases. It is the result of the growth of new blood vessels underneath the retina. These new vessels leak fluid or blood causing central vision to blur. The loss of vision can be quite rapid.
How can it be treated?
There are two possible approaches to treatment. Certain types of wet AMD can be treated with laser surgery designed to stop new blood vessels leaking.
Another option is photo dynamic therapy (PDT), a combination of drug and laser treatment aimed at slowing the leakage from the abnormal blood vessels.
Another approach targets a chemical in the body known to cause the growth of abnormal blood vessels under the retina. The chemical is called vascular endothelial growth factor (VEGF). Anti-VEGF drugs may help reduce the growth of these vessels.
Supplements in the form of a high dose of vitamin C, vitamin E, beta carotene and zinc can play a key role in maintaining vision in some people who are at risk of advanced AMD.
Unfortunately, while the various treatments will help preserve some sight they do not cure the problem to the extent that vision is restored. But macular degeneration on its own does not usually cause total blindness.
Even in advanced cases people retain some useful vision. In many cases, AMD’s impact can be minimal.