Phase 1 clinical trials have shown that a new therapy which uses viruses to introduce a gene into the eye is potentially safe for humans, and that it may be effective in preserving the vision of people with wet age-related macular degeneration.

The Johns Hopkins research team in Baltimore have developed a virus, similar to the common cold and modified to not cause disease, which is then used as a gene carrier. When injected in the eye the virus (“AVV2”) penetrates retinal cells and deposits a gene which stimulates the production of a therapeutic protein, which in turn halts the creation of abnormal blood vessels. This process could potentially eliminate the need to repeatedly inject the eye with protein, which is the common practice for many sufferers.

The research, however, comes with caveats - firstly, the scale of the trial was very small (19 men and women, aged over 50 with advanced wet AMD); secondly, although this preliminary clinical trial shows the treatment to be safe for humans, the research team states that broader use may have limitations due to a built-in immunity to the AAV2 virus among many adults.

Sources:

1. Science Daily:
   New gene therapy for vision loss is safe in humans, study suggests.

2. VisionAware:
   Treating Macular Degeneration with Gene Therapy: New Research Shows Promise but Also Has Limitations.