Eye Surgeons Miranda

Macular degeneration

The macula is the centre of the retina and affords your sharpest vision. As adults get older, many experience damage to their retinas which can lead to a increasing loss of central vision in that region of their macula, hence the term macular degeneration. If you have this condition, you find it difficult, even impossible, to read or to recognise faces. As well, contours, shadows and colour vision are less vivid. Macular degeneration is the leading cause of ‘legal’ blindness and severe vision loss in Australia.

Prevalence of Macular Degeneration

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Prevalence - Put simply, age-related macular degeneration (AMD) is the leading cause of irreversible blindness in Australia and other Western countries. While you won't become totally blind, you could well lose 35 percent of your visual field. Not to mention your driver's license.

Macular Susceptibility

Causes and those most at risk - There are two forms of macular degeneration: dry and wet. In the dry form cellular debris called drusen accumulate deep within the retina, sometimes causing the retina to become detached. In the wet, more serious form, blood vessels grow under the retina. This can also cause detachment of the retina. Even worse, bleeding, leakage and scarring from these blood vessels could in time cause irreversible damage to your photoreceptors, leading to rapid loss of vision.

Although some macular problems that affect younger people may be called macular degeneration, the term generally refers to the age-related variety. According to the Blue Mountains Eye Study, there is an exponential increase in the frequency of late-stage macular degeneration as you get older, with somewhat higher rates in women than in men. By pooling data from the Blue Mountains study along with two other studies, they found that “compared with the frequency in people aged 55-69 years, signs of late age-related macular degeneration were six times more frequent among those aged in their seventies and 25 times higher in those aged 80 years or older.”

They also found that besides age, several groups of factors appear to either increase or decrease the risk of age-related maculopathy. These include including smoking, vascular, familial, racial or ethnic, nutritional, hormonal, ocular or sunlight-related factors.

As suspected, current smokers had the highest risk of late-stage macular degeneration - four times that of past or non-smokers. The Blue Mountains researchers estimated that smoking may thus substantially contribute to around 20 percent of blindness in Australians aged over 50. Moreover, they also showed that smokers developed late-stage macular degeneration an average 10 years before nonsmokers.

Macular Warning Signs

Warning signs - You might not notice anything in the early stages. In fact, your vision could be quite good. One of the earliest changes seen in wet macular degeneration is distortion of straight lines. This is a serious anomaly and you should make an appointment with us straightaway. More than likely, any blood or swelling means you may have wet AMD. This is where distortion or a blob in your central vision may be apparent. In dry AMD our examination will reveal changes in pigment and yellow, plaque-like deposits in your macula - typical of dry AMD. These are the drusen mentioned earlier. Left untreated, they can grow in both size and number, eventually leading to advanced macular degeneration.

If you think you could be experiencing macular degeneration, there is a brilliantly simple self-test called the Amsler Grid. It is made up of a grid of horizontal and vertical lines, and if the lines you see are distorted or have missing patches, you likely have a disease of the macula. To download a PDF with the grid and instructions, just click Amsler Grid.

Macular Prevention

Preventative measures - For starters, if you smoke, stop! Giving up tobacco just might be the most important modifiable factor in preventing macular degeneration. You should also cut down on high-fat dairy products; have more cold-water fish and various nuts instead. The Macular Degeneration Foundation has put out a fact sheet that provides a lot of useful information about how your diet can help your eye health. For a PDF, click Nutrition & Supplements.

Macular Treatment

Treatment - We can treat the wet form of macular degeneration with laser or with medication that stops and sometimes reverses the growth of blood vessels. Recently, very effective new drugs called anti-angiogenics have appeared, which cause abnormal blood vessels growing in wet AMD to regress, improving vision. Administering them requires injection, but we carry out the procedure in our rooms under local anaesthetic, so you shouldn't feel much discomfort.

When it comes to the dry form, we don't recommend either medical or surgical treatment. Instead, we do two things. We educate you, explaining how wet AMD may develop and what the warning signs are, at the same time stressing the value of proper nutrition and the serious consequences of smoking. And we also prescribe vitamin supplements with high doses of antioxidants to slow the disease.

Macular Prognosis

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Prognosis - Dry AMD progresses over years and decades. So as long as you recognise the problem early and are diligent in taking preventative measures, you should be able to minimise the disease's impact.

Wet AMD, on the other hand, progresses over weeks and months. Fortunately, new treatments for wet AMD can stabilise or reverse vision loss. In this case though, it is even more important to diagnose and start treating the disease as soon as possible.

Probably the easiest way to cope with irreversible vision loss due to macular degeneration is by increasing both light and magnification. Vision Australia can be of great assistance in this regard, helping patients with mild to severe visual impairment regain their independence in a number of innovative ways. Handily, they recently opened a huge new centre just down the road in Caringbah.

Modern technology is also providing useful tools for those with visual impairments. Especially the ability to electronically magnify print. For example, instead of resorting to a hand-held magnifying glass, why not magnify your book text or newsprint with the new Apple iPad® (shown in landscape mode to the left)?