A single shot to keep blindness at bay?

Coming soon is a single shot that may keep blindness at bay.

Coming soon is a single shot that may keep blindness at bay.

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Yes, sight-saving drugs could one day be given without repeated injections into the eye, by temporarily breaching the blood-retina barrier, say scientists.

At present, drugs to treat age-related muscular degeneration, the leading cause of blindness, are injected in to the eyeball once a month. They cannot be injected into the blood partly because an eye lining normally prevents molecules in the blood from reaching the retina.

Now, a team led by Trinity College Dublin has restored the vision of mice by temporarily weakening this lining to let drug molecules injected into the blood slip through, the 'New Scientist' reported.

The scientists used a technique, RNA interference, to block the production of claudin-5, a protein that makes the blood-retina barrier impermeable. "It's proof of principle," lead scientist Matthew Campbell said.

In fact, RNAi therapy is not yet safe enough for use in people, however, as it would breach the blood-brain barrier as well as the blood-retina barrier.