cheap drug used to treat bowel cancer should also be prescribed to patients with a condition that leads to sight loss, say UK researchers.

英国研究人员称，一种用于治疗肠癌的廉价药物可用于易导致失明状况的患者。

Age-related macular degeneration leads to a progressive loss of sight
Avastin is not yet licensed for age-related macular degeneration（黄斑变性） , which is a leading cause of blindness in the UK.

But a study suggests the drug is "superior to standard care" and cheaper than the current medication, they report in the British Medical Journal.

Ministers have asked the drugs body NICE to explore its value.

Age-related macular degeneration (AMD) is also the leading cause of sight loss in patients over the age of 50 in Europe and North America.

"Dry" AMD is the most common form of the condition, which develops very slowly, causing gradual loss of central vision.

"Wet" AMD, which occurs in about one in 10 patients, can develop quickly and lead to sight loss.

Tests

Researchers at three eye centres in London, Bristol and Cheltenham carried out a pilot study（初步研究） in 131 patients with wet AMD.

They compared Avastin with the licensed drug, Lucentis, which costs about £10,000 per patient on average.

They concluded that Avastin was "superior to standard care".

Ophthalmologists（眼科医师） around the world have been injecting tiny quantities of Avastin into the eyes of patients on an experimental, or "off-label" basis.

They report success at low cost because one course can be split and used for dozens of patients.

The drug firm, Roche, which markets Avastin, has not applied for the drug to be used for wet AMD.

Barbara McLaughlan, RNIB campaigns manager for eye health and social care, said patients should continue to be treated with Lucentis until "robust（强健的，健康的） evidence" was available on the safety and effectiveness of Avastin.