What is the macula?
The retina lines the inside of the back two thirds of the eye and acts like the film in a camera. At the very centre of the retina is the macula which is the part of the eye that we use for reading and performing other detailed visual tasks. This gives us central vision, as opposed to peripheral vision which is served by the rest of the retina allowing perception of our surroundings and movement of objects within this.
What is macular degeneration?
When the macular deteriorates we call this degeneration and while this may occur as an inherited condition, it more commonly develops in the aging eye. Why this affects some older people and not others is not understood but it means that the patient may lose the ability to read and do other detailed functions.
Who gets it?
Some are born with an inherited disease which as they grow causes a deterioration in the retina some time in early to late teens. This is a very uncommon condition and leads to a loss of reading vision.
The commonest form of macular degeneration is that which occurs in older people which may cause a slow gradual deterioration in reading vision or a more sudden deterioration due to haemorrhage or leakage from blood vessels (disciform degeneration).
Can it be prevented?
Unfortunately the condition cannot be prevented but in some situations treatment with a laser beam can stop deterioration, particularly in those patients who are found to have a haemorrhage or leakage of fluid from the blood vessels. This situation is diagnosed using fluorescein angiography.
In this test a yellow dye called fluorescein is injected into a vein in the arm and circulates through the blood vessels of the eye which are then photographed.
Patients who lose or have defective reading vision can be helped with low visual aids such as magnifiers or closed circuit television. If the central vision is totally lost, talking books can replace the written word. More sophisticated aids with computers and talking typewriters can enable patients who lose central vision to continue to lead a normal life and occupation.