Understanding macular degeneration

Macular degeneration is a progressive and painless eye condition, which has the potential to cause vision loss in the centre of your visual field.

It’s the top cause of visual deficiency in industrialised countries, according to the World Health Organisation. Vision loss from macular degeneration does not cause a complete blackout — peripheral vision still remains. In extreme cases of the condition, sufferers may become legally blind.

The two main forms of macular degeneration are wet and dry. Dry macular degeneration is not as aggressive and generally does not cause as much vision loss as the wet form. Wet macular degeneration may cause sudden and severe vision loss. People who have dry macular degeneration are at risk of getting wet macular degeneration.

Glaucoma is not a type of macula degeneration. It is a different eye condition and affects the optic nerve, which also sits at the back of the eye.

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Macula 101

The macula sits on the retina and is instrumental in allowing clear central vision. Underneath the retina, there is a layer of cells called the retinal pigmented epithelium (RPE). The RPE transports oxygen and other nutrients from the blood vessels in the eye to the retina. It also transports waste materials from the retina back to the blood vessels.

When these retinal waste products aren’t transported through the RPE, they build up on the retina and are called drusen. Older patients often have drusen, which do not necessarily cause vision loss. However, having drusen in your eyes is a risk factor for getting macular degeneration.

What happens during macular degeneration?

In dry macular degeneration, the drusen may increase in number and size, and the surrounding retinal cells deteriorate. These changes result in loss to central vision.

In wet macular degeneration, abnormal blood vessels develop underneath the retina. These blood vessels have weaker walls, so the fluid within the vessels leaks into the retina. This leakage causes retinal scarring, which leads to severe vision loss.

Who’s at risk, and what you can do

Age is the biggest risk factor for macular degeneration – the older you are, the greater the odds of developing it. A history of smoking is another key risk factor.

Genetics also play a role: people who have an immediate family member with macular degeneration have a 50% chance of developing the condition themselves. Lesser risk factors include being female and of Anglo-Saxon ethnicity, obesity and high blood pressure.

Unfortunately, macular degeneration is incurable, so management of the condition aims to prevent further vision loss.

Currently for dry macular degeneration, there is no medical treatment. Recommended management tactics are to maintain a healthy diet and lifestyle, take supplements such as Macuvision, and have regular eye examinations with an optometrist or ophthalmologist.

Treatment for wet macular degeneration aims to maintain and stabilise vision, and can even improve it slightly. Vascular Endothelial Growth Factor (VEGF) is a protein that promotes the growth of abnormal blood vessels, which cause fluid leakage into the retina. Anti-VEGF drugs that stop this protein are injected into the eye to prevent abnormal blood vessel growth. Another treatment for wet macular degeneration involves directing laser light at abnormal blood vessels to seal or eradicate them.

Unfortunately, macular degeneration is not an avoidable condition. However, certain lifestyle choices can be helpful: these include not smoking, eating a well-balanced diet and protecting the eyes from UV rays.

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