06 Dec Macular Degeneration
What is it?
Macular degeneration is the leading cause of severe, irreversible vision loss in people over the age of 60. It occurs when the small, central portion of the retina – known as the macula – deteriorates. The retina is the light-sensing nerve tissue at the back of the eye. Because the disease develops as a person ages, it is often referred to as age-related macular degeneration (AMD). Although macular degeneration almost never leads to complete blindness, it can be a source of significant visual disability.
There are two main types of age-related macular degeneration:
- The “dry” form of macular degeneration is characterised by the presence of yellow deposits, called drusen, in the macula. A few small drusen may not cause changes in vision; however, as they grow in size and increase in number, they may lead to a dimming or distortion of vision most noticeable when reading. In the advanced stages, patients lose central vision.
- The “wet” form of macular degeneration is characterised by the growth of abnormal blood vessels from the choroid underneath the macula. These blood vessels leak blood and fluid into the retina, causing distortion of vision that makes straight lines look wavy, as well as blind spots and loss of central vision. These abnormal blood vessels and their bleeding eventually form a scar, leading to permanent loss of central vision.
Most patients with macular degeneration have the dry form of the disease and can lose some form of central vision. However, the dry form of macular degeneration can progress to the wet form.
Symptoms of macular degeneration include dark, blurry areas in the centre of the visual field and diminished or changed colour perception.
Early detection of age-related macular degeneration is very important because there are treatments that can delay or reduce the severity of the disease.
How is it treated?
There is currently no cure for macular degeneration, but treatments may prevent severe vision loss or slow the progression of the disease considerably.
Treatment options include:
The Age-Related Eye Disease Study (AREDS), published in 2001 by the National Eye Institute of the National Institutes of Health (USA), showed that taking supplements with high levels of the carotenoids Lutein and Zeaxanthin, as well as vitamins C and E, zinc and copper and omega-3 fatty acids can slow down the progression of AMD. Supplementation containing these substances is therefore recommended.
Anti-angiogenesis drugs block the development of new blood vessels and leakage from the abnormal vessels within the eye that cause wet macular degeneration.
Photodynamic laser therapy may also be used. During this two-step treatment, the doctor injects a light-sensitive drug into the bloodstream, which is absorbed by the abnormal blood vessels in the eye. The doctor then shines a cold laser into the eye to activate the drug, damaging the abnormal blood vessels.