The macula is a specialised region of the retina (the tissue located at the back of the eye that detects light), which is responsible for our highly detailed vision. This includes tasks like recognising faces, reading a book and driving. Age-related macular degeneration (also known as AMD) is a disease that occurs with increasing age and is very common with one in seven people over 50 affected by the condition. AMD becomes more common with increasing age and one in four people over 80 have vision loss due to AMD.
The macula’s function is progressively impaired in AMD, leading to permanent loss of our high-detailed vision. Age related macular degeneration can progress in one of two ways; the dry form or the wet form.
Dry AMD is the more common form of the disease and progresses slowly. In the earliest stages, dry AMD does not have any symptoms and as the disease progresses the only symptom is gradual blurring of the central vision. However, when dry AMD converts to wet AMD, vision loss can occur suddenly and profoundly, meaning your vision can become very poor, very quickly (within minutes).
It is important to note that once AMD develops, it is present for life. Furthermore, once vision loss due to AMD occurs, it cannot be recovered. However, you can prevent severe vision loss from occurring in the first place by undertaking regular eye examinations to detect the condition in its earliest stages. This allows treatment to be initiated as soon as AMD develops thereby limiting vision loss.
Fortunately, there are treatments for AMD which can prevent vision loss if initiated early enough. These treatments are primarily aimed at preventing disease progression.
Age-related macular degeneration affects over 200,000 people in New Zealand over 50 and is one of our leading causes of blindness. Early signs of the condition can develop earlier in life and have no symptoms. We recommend that everyone has regular eye examinations with our optometrists as the specialised tests conducted on everyone can detect AMD in its earliest stages and the steps to prevent vision loss can be taken.
Several life-style factors are known to increase the risk of developing AMD, including: being over-weight, smoking, too much sunlight sunlight exposure, and diet. These factors can of course be modified, particularly smoking as those who smoke are three times more likely to develop AMD and do so 10 years earlier than non-smokers. There is also a genetic component to AMD (which cannot be modified), so if an immediate family member has the condition, you are at greater risk of developing it yourself.
Diet modification is extremely important. Consuming as much fruit and vegetables as possible, including leafy greens such as kale and silver beet is highly beneficial. There have been two large investigations into what nutrients may be effective at preventing the progression of AMD, called the AREDS or age-related eye disease study 1 and 2. These studies have revealed that the following should be consumed as they may prevent AMD progression: 500mg of vitamin C, 400 international units of vitamin E, 80mg zinc as zinc oxide, 2mg copper as cupric oxide, 10mg lutein and 2mg zeaxanthin. Obtaining this from diet alone is practically impossible as such a supplement in the form of a tablet is the best way to obtain these nutrients. Your optometrist will be able to recommend the best supplement for you.
Monitoring with an Amsler Grid
The Amsler grid is a grid pattern specifically designed to monitor AMD at home. The grid should be looked at with each eye individually i.e. one eye covered then switch to the other eye. If any of the grid lines are wavy, broken or distorted, or if any part of the grid is blurry or areas are missing, this is an indication that AMD has progressed and care should be sought immediately.
Complimentary Amsler grid charts are available from Mortimer Hirst.