Definition of MD
The back of the eye is lined by a layer of light-sensitive cells (the retina), which houses a central region (the macula) that is involved in the sharp, detailed, colour vision needed to perform daily activities such as reading or driving. Macular Degeneration (MD), the leading cause of blindness in Australia, is a chronic degenerative process affecting the macula. This leads to progressive, painless loss of central vision. Sparing of the peripheral areas of the retina means that total blindness does not occur in MD.
An estimated 1 in 7 Australians over the age of 50 are reported to have some degree of Macular Degeneration, with incidence increasing with age, despite the fact that this disease can also affect the younger population. In 2010, an estimated 1.023 million Australians lived with AMD. If effective preventative measures and treatments are not introduced, this number is expected to rise to 1.77 million people by 2030 due to the ageing population.
Effects of MD
The development of MD involves the retinal pigment epithelium (RPE). This is a special layer of cells lying behind the retina. It nourishes the retina and removes its wastes. If these wastes accumulate beneath the RPE over time, yellow spots known as drusen may form. While these can be harmless, the formation and accumulation of drusen may reflect the development of early-stage MD (or early age-related maculopathy), which increases the risk of vision loss. Late-stage MD (or age-related macular degeneration [AMD]) occurs with progressive loss of central vision, which results from either:
Various factors contribute to the risk of developing MD, including age, genetics, smoking, high blood pressure, and diet. Regular eye tests, a healthy lifestyle with good diet and exercise, and various vitamin and mineral supplements, can improve eye health and thus decrease risks of developing MD.
The estimated cost of vision loss associated with AMD was $5.15 billion in 2010. Unless effective preventative or treatment efforts are developed and implemented, the number of people who lose central vision and the cost associated with this disease will continue to rise with the ageing Australian population. (Macular Degeneration Foundation. (2011). Eyes on the future: A clear outlook on Age-related Macular Degeneration. Prepared by Access Economics and Professor Paul Mitchell for the Macular Degeneration Foundation, Sydney.)
Treatment Options for AMD
While treatments for dry AMD are still under investigation, studies have shown that wet AMD can be effectively treated and stabilized by injections of antibodies that inhibit “Vascular Endothelial Growth Factor” (VEGF) into the eye. VEGF is responsible for the overgrowth of leaking blood vessels under the retina. Anti-VEGF drugs prevent and may reverse this process if the disease is detected early.
In the past, laser photocoagulation and photodynamic therapy, which also blocked the progression of abnormal retinal blood vessel formation by “spot-welding” the leaky vessels, were widely used. However, laser photocoagulation is not very effective in stabilizing the disease and also involves risk of vision loss, and photodynamic therapy has been largely replaced by anti-VEGF therapy.
Any sudden changes in vision should be reported to your eye specialist as soon as possible, as a delay in treatment can lead to vision loss.