Check-up: Age-related Macular Degeneration

Can you tell me what AMD is?

The retina is the layer of tissue at the back of the inner eye, which changes the light and images from the eye so that they can travel via nerve signals to the brain.

The macula is the part of the retina that makes our vision sharper and more detailed. Damage to the blood vessels that supply the macula make it difficult to see fine detail. Age-related macular degeneration (AMD) is most common in people over 60.

There are two types of AMD. Dry macular degeneration occurs when the blood vessels under the macula become thin and brittle. Small yellow deposits form under the macula, creating a blurred and dim spot in the central vision of the eye. Wet macular degeneration occurs in approximately 10 per cent of people with AMD. It is caused when brittle vessels break down and new, fragile blood vessels grow under the macula. These new vessels can leak causing damage to the macula.

What are the symptoms and treatment of AMD?

The most common symptom of dry AMD is blurred vision in the centre of the field of vision. This makes objects look distorted and faded. Although it may be difficult to read print or see detail, sight is usually adequate enough to perform routine activities.

As the disease progresses, more light may be needed to read or perform tasks. The blurred spot in the centre of vision tends to get gradually larger and darker.

In the later stages, it may be difficult to recognise faces unless within very close range. AMD typically does not affect peripheral vision, which means that complete vision loss does not usually result from this disease.

The most common early symptom of wet macular degeneration is that straight lines appear distorted and wavy. A small dark spot in the centre of vision tends to get gradually larger. Central vision loss can occur very quickly.

Although there is no treatment for dry macular degeneration, a combination of vitamins, antioxidants and zinc may slow the progression of the disease. Treatment for wet AMD includes laser surgery and photodynamic therapy – a light activates a drug injected into the body to destroy leaking blood vessels. Special drugs injected into the eye can help slow the formation of new blood vessels and stabilise vision.

Low-vision aids can help improve quality of life.