Expert warns that an unhealthy lifestyle can lead to vision loss

Feb 9 2009

A leading Australian eye expert has warned that people who do not adopt a healthy life style can expect a loss of vision in later life.

According to Professor Jan Provis from the ARC Centre of Excellence in Vision Science (The Vision Centre) and The Australian National University there is a growing epidemic of vision loss as people age and an aggressive public health campaign is needed to address the problem.

Professor Provis says not smoking, keeping fit, eating a healthy diet rich in fish oils, low in fats and high in antioxidants, are all ways to slow the degeneration of the macula, the eye's most critical region for clear vision.

Professor Provis says the macula is why humans have remarkably acute vision - the macula is a small spot on the inside back of the eyeball that does most of our useful seeing, such as reading, recognising faces and spatial resolution and for the first 50 years of life presents no problem, but then it starts to degrade and this leads to partial and sometime total loss of sight.

Some of the conditions which can have devastating consequences for people who are still otherwise active are Age-related Macular Degeneration (AMD), Bests' Disease, Stargardts' Disease and Macular Telangiectstasis.

Professor Provis says research indicates that this is due to an evolutionary trade-off which has occurred in humans and other primates over time - we have developed extremely acute vision, partly because the number of blood vessels in the macula - and its central region, the fovea - is quite low - having too many blood vessels would obscure our vision, so we have settled for a compromise: sharp vision in youth - but an unstable macula that deteriorates over time.

Professor Provis says human eyes consist of very large numbers of neurons which combine to enable us to see well, and these demand quite large amounts of oxygen - however having fewer blood vessels, the neurons in the macula can easily be starved of oxygen causing them to die in large numbers and this contributes to the typical decline in vision from mid-life onwards that most of us experience.

She says while little can be done at present to reverse this degeneration, there are things which can slow or prevent it and these in the main involve keeping the blood circulatory system in good order.

Professor Provis says it is acknowledged that various lifestyle choices like smoking, eating a fatty diet and not enough fish and fresh fruit all tend to damage the health of capillaries - the fine blood vessels that deliver the oxygen to critical regions throughout our bodies - this also applies to the capillaries that supply oxygen to the macula.

Professor Provis and her team have identified 25 genes that regulate blood vessel growth within the macula and they hope this may eventually lead to therapies for treating macular disease and better public health advice on how to avoid it.

Professor Provis believes enough is already known about the process of degeneration of eyesight with age to warrant an aggressive public health campaign to encourage people to keep their circulatory system in better order from a younger age.

Professor Provis says in an ageing population, the loss of vision is major concern as it carries major public health and caring costs, limits people's independence, their ability to support themselves and to enjoy their later years and can be addressed in the same way that we are addressing conditions such as heart disease, skin cancer and diabetes - through education and changes in our behaviour.