Sight

CATARACT
This is a clouding of the lens which means that light beams do not pass straight through the lens to create a focused image, but are scattered in different directions, creating a blurred image. The initial symptoms may include seeing double (if the cloudiness is in more than one place) or images looking blurred round the edges, or 'fuzzy.'

MACULAR DEGENERATION

At the back of the eye in the retina there is a spot called the macula which is responsible for the central part of our vision. If this spot becomes damaged or misplaced then the central part of vision deteriorates, leaving only peripheral vision. Sufferers will still be able to find their way around, but will lose the ability to read and write, watch TV and carry out other activities which require detailed vision.

GLAUCOMA

Glaucoma develops when the optic nerve at the back of the eye is damaged by raised pressure within the eye. There are several different types of glaucoma; the most common (80% of sufferers) is "open angle glaucoma" which occurs when pressure rises in the eye if the amount of nourishing fluid (aqueous humour) within the eye increases. Eventually the pressure build up damages the optic nerve and visual field decreases. As vision deteriorates over years, often in both eyes simultaneously, with no other symptoms, glaucoma may not be diagnosed until it is well advanced.

Incidence

All three conditions increase in frequency with age. The largest studies in Britain have concentrated on prevalence in 75-85 year olds, and have shown in this group 42% suffer from some degree of cataract, and 39% from macular degeneration , with women more likely to suffer than men in both cases. 7% suffer from open angle glaucoma with a predominance in men. Some patients suffer from more than one condition simultaneously.

Cataract Prevention

Prevention of cataracts is not currently possible, but several risk factors have been identified, and researchers are investigating certain substances which seem to reduce the incidence of cataracts. The risk factors that have been identified so far are:
Diabetes - diabetes increases the risk of cataract four fold.

Smoking - smoking 20 cigarettes a day doubles the risk of cataract.

Excessive alcohol intake - A regular intake of 4 units of alcohol a day will increase the risk of a cataract.

Steroids - Long term intake of some steroids will increase the risk.

Diarrhoea - Severe bouts in older people, especially in older people increase the possibility of cataract probably because of the of the dehydration produced.

On the prevention side, studies are showing that consumption of small amounts of analgesics (eg aspirin, paracetamol, ibuprofen) offers significant protection against cataract.A high intake of antioxidant vitamins, ( E & C ) has also been shown to help prevent cataract , so it may be important to maintain a high intake of fruit and vegetables.

Once a cataract has formed, the most effective treatment is surgical removal of the clouded lens This is usually done when the sufferer finds it difficult to see, and activities are restricted . Removing the lens is a small operation, sometimes done on a day patient basis, but it will not by itself restore normal vision because of the importance of the lens in focusing. Special cataract glasses and contact lenses both have their problems, and a plastic lens implant at the time of the operation is a common procedure. The success rate of the operation is very high.

MACULAR DEGENERATION

Because the causes of macular degeneration are not yet understood (hence the need for urgent research ) , treatment is often not possible, although some patients may be helped by laser treatment if the condition is diagnosed early enough. Peripheral vision is a great help and some people can carry on with many of their daily activities. Better lighting and magnifying devices may help with some problems.

GLAUCOMA

The objective of treatment is to reduce the pressure in the eye to normal and so to prevent the damage that raised pressure causes. Treatment may be started with eye drops, used regularly several times a day. If this does not work, surgery or sometimes laser treatment will be tried. Since there is no cure and damage to the optic nerve cannot be reversed, early diagnosis is essential so that regular checks, regular eye drops and, if necessary, surgery can keep damage to a minimum and good vision preserved indefinitely.

There is a need for more research. Whilst research into the causes of cataract seems to be fairly well established, there is still a great deal required to discover how to PREVENT cataract so that the trauma of cataract operations (120.000 are performed in Britain each year) can be avoided. Also, although the majority of cataract operations are successful, complications do arise in up to 10% of cases, and secondary cataract can occur after 2 or 3 years necessitating another operation. All of these problems could be avoided by further research. Even less is known about risk factors, preventative strategies and treatment for macular degeneration and glaucoma. As these conditions increase in frequency with age, and as we have an ageing population it is vital that the level of research is increased so that dependency through loss of vision does not become a normal part of the ageing process.

Contact
Royal National Institute of Blind People
105 Judd Street
London
WC1H 9NE

Tel: 020 7388 1266
Fax: 020 7388 2034

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