Fresh hopes of cure for blindness in the over-50s

Faulty immune system could result in cholesterol build-up, the main cause of eye disease in the elderly

THERE may soon be a cure for the leading cause of blindness in people over 50 after scientists discovered agerelated macular degeneration could be caused by a faulty immune system.

It is known that a build-up of cholesterol in the eyes can trigger sight loss through AMD, but researchers did not know why it happened.

Experts at Washington University found that the condition could be induced in mice by knocking out genes that tell immune cells to clear away the cholesterol. Their study suggests AMD is caused through ageing, when the immune system stops working as effectively, and fails to remove cholesterol from the eyes.

The breakthrough brings the hope that treatments could be developed to keep the immune system functioning correctly and prevent AMD. The disease affects more than 600,000 people in Britain and occurs when light-sensitive cells at the centre of the retina – the macular – are damaged.

Over time, patients experience increasingly blurred vision or blindness emerging from the centre of the visual field. The condition comes in two forms, one of which can cause irreversible blindness within weeks.

Rajendra Apte, professor of ophthalmology at Washington University School of Medicine and a co-author of the study, explained that “systemic and local abnormalities in cholesterol processing” can contribute to AMD and can also serve as biomarkers for the disease. “What we have now identified is how these deposits actually happen to form and created mice that mimic many features of the human condition,” he said.

“What is exciting about this is that now, for the first time, we can test therapeutics directly to see which ones might prevent the disease from developing or can prevent complications of the disease.” The only treatments commonly available for AMD sufferers are injections in the eye or laser surgery. However, they only partially restore sight and do not work for everyone.

Earlier this year, scientists from University College and Moorfields Eye Hospital in London were able to restore the sight of two AMD patients using stem cell patches that replenish the damaged area.

The Washington University study was published in the Journal of Clinical Investigation.