Over a half a million Britons over the age of 75 have extremely poor eyesight, a study has revealed.

Research carried out by experts in London has found that one in 10 elderly people is visually impaired and one in 50 is blind.

It also showed that poor eyesight affects women more, with three out of four likely to have serious difficulties by the age of 75.

It highlights the real problems in the over 75's category

RNIB spokesman

But scientists at the Moorfields Eye Hospital in London said the real figures are probably much higher because people in nursing homes were not included in the study and the elderly are less likely to have their eyes examined.

The figures suggest that more people need expert eye care than are currently receiving it.

Cross-section

Jennifer Evans and colleagues studied eyesight tests and information from blindness registries on 14,600 elderly people.

The patients came from a cross section of 53 general practices across the UK.

Using World Health Organisation criteria, they estimated that 10% of these patients were visually impaired and 2% were blind.

Almost 20% had such bad eyesight that they would not be permitted to drive. This rose to almost half of those over the age of 90.

The researchers estimated that in the general population over 600,000 elderly people are visually impaired. One third of these are over 90 years of age and 75% are women.

Writing in the British Journal of Ophthalmology, the authors stated: "Our results confirm that visual impairment is common in this age group and that the risk of visual impairment including low vision and blindness increases steeply in these older age groups."

They added that the finding "highlights the need for prompt attention to the ophthalmic needs of this group".

Exciting results

The Royal National Institute of the Blind said the findings highlighted the need for greater medical intervention to help old people who are losing their sight.

A spokesman said: "The Royal National Institute of the Blind is very excited by the results.

"It highlights the real problems in the over 75's category and builds on other work.

"RNIB is in close discussion with the authors of the paper to discuss the implications of this research."

Macular degeneration is a leading cause of blindness in the elderly. The condition is caused by the deterioration of the central portion of the retina, which is known as the macula.

People with macular degeneration have difficulty reading, driving, recognising faces and seeing objects in detail.