Scientists are trying for the first time to end the most common cause of age-related blindness with gene therapy

Surgeons have tried for the first time to end a common form of blindness with a single injection of gene therapy.

For 12 years, a team at the University of Oxford has been experimenting with gene therapy to slow or stop the progression of different eye conditions.

But until now, most of the treatments they have done have been for relatively rare problems, such as choroideremia, which affects 1,200 people in Britain, and retinitis pigmentosa, which affects 16 000 people.

Now, surgeons have launched their first attempt to stop age-related macular degeneration – AMD – which is the most common cause of blindness and affects 600,000 people in the UK.

The team is currently conducting a clinical trial of ten patients at Oxford Eye Hospital.

The small test is primarily designed to test its safety – but it should eventually indicate whether the treatment will work or not, in which case a much larger trial will be launched.

The first patient, 80-year-old Janet Osborne, who underwent treatment under local anesthetic last month, said the central vision of her left eye was deteriorated and very hazy, making housework very difficult.

"I always enjoy gardening with my husband, Nick, who grows a lot of vegetables," she told BBC News.

"If I could continue to peel and cut vegetables and keep my current level of independence, it would be absolutely wonderful.

"I did not think of myself.

"I was thinking about other people. For me, I hope my eyesight does not get worse. It would be fantastic. This means that I would not be such a nuisance for my family. "

Professor Robert MacLaren, project leader, whose trial is funded by gene therapy company Gyroscope Therapeutics, said, "AMD is the leading cause of incurable blindness in developed countries.

"Genetic therapy administered early to preserve the vision of patients who lose their sight would be a major advance and certainly what I hope to see in the near future."

The trial focuses on dry AMD, which involves a slow deterioration of cells at the back of the eye.

It affects the central part of the patient's vision with gaps or "spots", making everyday activities such as reading and recognizing faces difficult.

The operation involves detaching the retina and injecting a solution containing a virus underneath.

The virus contains a modified DNA sequence, which infects cells and corrects the genetic defect at the origin of AMD.

Ideally, if successful, gene therapy should be done only once, as it is thought to last for a long time.

Professor MacLaren said, "We are exploiting the power of the virus, a natural organism, to deliver DNA into the patient's cells.

"When the virus opens inside the retinal cell, it releases the DNA of the gene we cloned. The cell begins to make a protein that we believe can alter the disease, correcting the imbalance of inflammation caused by the complement system.

"The idea of ​​this gene therapy is to" disable "the complement system, but at a very precise point in the back of the eye, so that the patient is not affected by it and we hope that in the future this will slow the progression of macular degeneration. The surgeons hope that the current trial will show that they can stop the progression of the disease and preserve the remaining vision of the patients.

But in the future, they hope to experiment with this drug on patients with early AMD and stop the disease even before their vision begins to deteriorate.

Professor MacLaren said, "I hope we will see a cure for people with dry AMD in the next few years."