Sunday, April 12, 2009

Eye 'compensates for blind spot'

Partially sighted and registered blind people can be taught to read and see faces again using the undamaged parts of their eyes, say experts.

When only the central vision is lost, as with the leading cause of blindness, age-related macular degeneration, peripheral vision remains intact.

And patients can be taught to exploit this, the Macular Disease Society says.

It has developed a training scheme and is calling for professionals to adopt the system across the UK.

The macula is a small area of the retina at the back of the eye made up of specialist cells which process central vision as well as the fine detail of what we see.

People with macular degeneration rarely go totally blind but even those with a relatively mild version of the disease cannot drive and have difficulty reading, recognising faces and watching television.

But studies show people can be taught to use their peripheral vision to fill in the gaps, using "eccentric viewing" and "steady eye techniques".

When someone with central vision loss looks directly at an object it may disappear, go faint, blur or distort. But when they look above, below or to one side of it, they see it more clearly.

Blind spots

Eccentric viewing helps people find exactly where to focus their gaze to make their vision better.

Once this position is identified, they can be taught how to read again using the steady eye technique.

Instead of moving the eyes from left to right to read a sentence, the person should keep their eyes completely still and move the text to the left so that each word in turn moves into the area of best vision.

Macular Disease Society chief executive Tom Bremridge said: "Eccentric viewing works by making the most of vision that remains.

"Our scheme has transformed lives - helping people to relearn basic skills they thought to have lost for good.

"We have 86 volunteer trainers, all with central vision loss themselves, who have trained more than 310 people in their own communities, and our waiting list of nearly 1,200 people grows every day.

"We are keen that other service providers - social services, private practitioners and primary care trusts - now take up the baton."

Mr Winfried Amoaku, of the Royal College of Ophthalmologists, said eccentric viewing could help some patients with central vision loss "cope with everyday tasks such as identifying coins while out shopping, watching television and reading".

"The trouble is, we don't know who will benefit until they have tried the training.

"All UK patients with central vision loss should have the opportunity to try eccentric viewing techniques to see if they can benefit," he said.

Marek Karas, of the Royal National Institute of Blind People, also supported the research advances.

"Although there is still ongoing discussion among experts over the best form of training for this type of therapy, we welcome with interest these latest developments."

Between 25 and 30 million people worldwide have macular degeneration. But as the population ages, this figure will rise.

It is estimated that the number of people affected will triple by 2025.