Preventing vision loss as you age
The Australian Bureau of Statistics records as of 2005 approximately 17,000 blind people residing in NSW, and an additional 160,000 people with severe impairment of vision. One of the leading causes of vision loss in Australians is what is known as ‘age-related macular degeneration’, or AMD.
This is a disease common among people over 60, and involves the central part of the retina, the light sensitive tissue lining the inner surface of the eye. With this condition the tissues of the retina deteriorate, which results in whatever is looked at directly will be hard to see. There are two kinds of AMD, wet and dry.
Wet forms of AMD are caused by blood vessels growing abnormally underneath the macula, the small highly sensitive area near the centre of the retina. These blood vessels can rupture and bleed, causing scarring and blurred vision. The dry form of AMD is caused by the macula degenerating over time and losing function. Either form makes reading or driving impossible, and profoundly affects one’s quality of life.
Researchers from the Brigham and Womens Hospital, working with Harvard Medical School epidemiologists, have recently completed a 7-year study that found a way that may help prevent AMD. Until now the only known prevention has been avoiding cigarette smoking, as tobacco use is the major preventable risk factor for AMD. It is believed that the nicotine in cigarettes is responsible for stimulating vessel growth in the retina.
The benefits to the eyes of giving up tobacco are very real: people who stopped smoking 20 years ago have the same risk of developing AMD as non-smokers. Otherwise you are doubling your chances of sight loss later in life with every cigarette.
The ‘randomised, double-blind clinical trial’ (which means that neither the 5,442 female participants over 40, nor their doctors, knew whether they were assigned to take placebos or the vitamins) looked at the effect of several vitamins on the disease. The results were promising; they found that by taking vitamins B6, B9 (folic acid) and B12, there was a 41 percent lower risk of developing the more severe forms of AMD. These B vitamins lower the levels of homocysteine, an amino acid found in the blood, which is also a known marker for cardiovascular disease and increased fractures.
The researchers say that it is too early to act on their findings, and that more research is needed before they recommend everyone take the various vitamins B. However, the researchers were able to point to the 10-year ‘Age – Related Eye Disease Study’ conducted by the National Eye Institute of the US National Institutes of Health which discovered that taking the antioxidant vitamins A, E, C and zinc could prevent the progression of the disease, which they did recommend at this time.
Although there is very little risk in also adding a multi-vitamin containing the B6, B9 (folic acid) and B12, it is always best to discuss such decisions about vitamins and supplements with your GP or dietitian to make sure they don’t interact with any of your medications. For more information about macular degeneration please click here.