Age-related Macular Degeneration

Age-Related Macular Degeneration (AMD) is the most common cause of vision loss in Australia.

Distortion is an important symptom that should be seen too as soon as possible.

What is AMD?

Age-related macular degeneration (AMD) is a degenerative condition effecting the central area of the retina called the macula. The macula is a small area at the back of the eye which is responsible for fine and reading vision. Conditions effecting the macula reduce central vision, leaving the peripheral vision intact. For example, you could see the outline of a clock but not be able to tell what time it is. It effects both distance and close vision and can make some activities, like reading, difficult or impossible

How Common is AMD?

AMD is the most common cause of vision loss in Australia. In people aged in their 50s, end stage AMD is found in 1-2% of people. This number increases to 28% in people in their 80s.

What are the symptoms of AMD?

Age-related macular degeneration can cause different symptoms in different people. The condition can be hardly noticeable in its early stages. Initially patients notice difficulties with performing near tasks. Reading may become more difficult, with the print fading or running together and brighter illumination required. Straight lines may also look distorted.

Central vision may later become very poor with dark or empty areas appearing in the centre of vision.

What are the causes and risk factors?

Many older people develop AMD as part of the body's natural aging process. AMD may run in families but many cases do not seem to have a family history.

Staff at the Centre for Eye Research Australia have been collecting blood from people with this condition in an attempt to find the genes responsible for AMD. Finding the genes involved would help us detect people at risk at an early age and help us find more effective treatments for AMD.

We also now know that smoking increases the risk of severe visual loss from AMD six fold.

Types of AMD

Two common forms of AMD are dry (atrophic) and wet (exudative).

Most people have dry AMD. It is caused by the thinning of the tissues at the macula. Vision loss is usually gradual.

The wet form is characterised by the development of abnormal vascular membranes beneath the retina which may leak fluid or bleed, eventually resulting in a scar at the macula. The early detection of this complication by using an Amsler Chart is essential as prompt treatment is required in order to achieve the best visual outcome.

Treatment for AMD

Unfortunately, the cause of macular degeneration is still unknown. Although your ophthalmologist will be able to readily detect the disease during an eye exam, he or she may not be able to cure it. The aim in most cases is to help stabilize the condition and reduce the severity of vision loss.

The dry form of AMD has no effective treatment at present. A healthy diet with fresh fruit and green vegetables is recommended as this provides nutrients and antioxidants which may slow the progression of dry AMD.

The abnormal vascular membranes that develop in the wet form may sometimes be treated with laser to the retina - this is a brief and usually painless outpatient procedure. The treatment is more likely to be able to be used the earlier the patient is seen. The laser seals the leaking blood vessels that eventually damage the macula. Although a small blind spot is left in the area treated by laser the procedure may limit the size of the eventual area of visual loss.

Photodynamic therapy has been found to be effective in slowing the rate of visual loss for some cases of AMD. Newer trreatments known as Anti-VEGF agents which slow the proliferation of the abnormal blood vessels have shown promise in clinical trials and may be available in the near future. Other treatments such as radiotherapy and retinal surgery have not been shown to be effective in the management fo exudative AMD.

Despite the advances in medical treatment, people with macular degeneration continue to experience visual loss. Although people who have AMD experience mild to severe central vision loss, it does not effect perifieral vision, and therefore one does not go blind from AMD. With the help of low vision aids, people can continue with many of their favorite activities and still lead normal, independent lives.