Multiple sclerosis patients are being given hope following trials of a drug made from goats' blood, doctors say.
Some MS patients have problems with vision
An Oxford University study found two weeks of injections of the anti-inflammatory drug improved the vision of the 11 patients.
One of the most common features of MS, which affects 80,000 people in the UK, is problems with eyesight caused by inflammation of the optic nerve.
MS experts said more research was needed into the treatment.
The drug, called Aimspro, is not licensed in any country yet, but makers Daval International said they hoped to be granted one within a year.
More than 200 UK patients are being treated with Aimspro on a named patients basis whereby the doctors take responsibility for giving the drug.
It is the first time that any treatment has been shown to reduce an aspect of disability in the chronic phases of the disease, a degenerative disorder of the nervous system.
Oxford University's professor of neurology Paul Matthews, who led the trial at the John Radcliffe Hospital, said the results were "encouraging".
"By studying the effects of a drug on vision in patients with optic neuritis we can reasonably expect to understand possible effects of the drug on the disease as it affects other parts of the brain."
But he added more investigations into the drug were needed.
Brian Quick, chief executive of Daval, said: "It's a drug we believe, based on empirical and clinical evidence, to have a broad application to fight MS, relieving its symptoms and improving the quality of life of MS sufferers.
"But we are also investigating its potential as a treatment for a host of other conditions including inherited diseases of nerves, muscular dystrophy and some very rare and previously untreatable conditions."
Mike O'Donovan, chief executive of the MS Society, said: "This research adds weight to the promising anecdotal evidence which has been reported for this treatment.
"We are keen to see the investigations taken further," he said.