A gene therapy that deliberately infects the eye with a virus can safely preserve vision in people affected by one of the leading causes of blindness, research has shown.

In a small preliminary study, scientists used an altered common cold-type virus to carry a repair gene that combats age-related macular degeneration (AMD).

The disease is marked by abnormal blood vessels that leak fluid into the central part of the retina, or macula.

After being injected into patients' eyes, the virus penetrated retinal cells and deposited the gene, which manufactured a therapeutic protein called FLT01.

Lead researcher Professor Peter Campochiaro, from Johns Hopkins University in the US, said: “This preliminary study is a small but promising step towards a new approach that will not only reduce doctor visits and the anxiety and discomfort associated with repeated injections in the eye, but may improve long-term outcomes.”

The Phase I clinical trial involved 19 men and women aged 50 and older with advanced “wet” AMD.

With the help of the gene, retinal cells were turned into “factories” making FLT01.

Best Universities for Life Sciences and Medicine Show all 20 1 /20 Best Universities for Life Sciences and Medicine Best Universities for Life Sciences and Medicine Harvard University Flickr/Michael Hicks Best Universities for Life Sciences and Medicine Cambridge University Flickr/John Menard Best Universities for Life Sciences and Medicine Oxford University, All Souls College Tejvan Pettinger/CC BY 2.0 Best Universities for Life Sciences and Medicine Massachusetts Institute of Technology Flickr/Justin Jensen Best Universities for Life Sciences and Medicine Stanford University Flickr/Franco Folini Best Universities for Life Sciences and Medicine John Hopkins University Flickr/David Wilson Best Universities for Life Sciences and Medicine Karolinska Institutet, Main entrance from Solnavägen with the 'Aula Medica' in the background Creative Commons Best Universities for Life Sciences and Medicine University of California, Los Angeles campus Flickr/Tzuhsun Hsu Best Universities for Life Sciences and Medicine University of California, Hastings College of Law Flickr/Ken Lund Best Universities for Life Sciences and Medicine Yale University's Beinecke Rare Book and Manuscript Library Flickr/Lauren Manning Best Universities for Life Sciences and Medicine UCL University, London Flickr/Neil Turner Best Universities for Life Sciences and Medicine Imperial College, London Flickr/Andrew Crump Best Universities for Life Sciences and Medicine University of Melbourne Flickr/Geoff Penaluna Best Universities for Life Sciences and Medicine Berkeley University Flickr/Charlie Nguyen Best Universities for Life Sciences and Medicine University of Toronto Flickr/Umair Khan Best Universities for Life Sciences and Medicine The Geisel Library on the San Diego campus of the University of California Flickr/O Palsson Best Universities for Life Sciences and Medicine University of Sydney Flickr/Jason Tong Best Universities for Life Sciences and Medicine Kings College London iStock Best Universities for Life Sciences and Medicine Duke University Flickr/Carine06 Best Universities for Life Sciences and Medicine University of Singapore Flickr/smuconlaw

The scientists hope this will eliminate the need to administer repeated injections of the protein, which suppresses a natural growth-driving molecule called VEGF.

“Prolonged suppression of VEGF is needed to preserve vision, and that is difficult to achieve with repeated injections because life often gets in the way,” said Prof Campochiaro.

For safety and ethical reasons, the patient group consisted of people for whom standard approved treatments were highly unlikely to restore vision.

Only 11 patients stood any chance of fluid reduction. Of those, four showed dramatic improvements after the gene therapy. The amount of fluid in their eyes dropped from a “severe” level to almost nothing.

Two other patients experienced a partial reduction in the amount of fluid in their eyes.

The findings are reported in the latest issue of The Lancet medical journal.

