Stem cells restore sight in new study

Embryonic stem cells transplanted into 18 patients with deteriorating eyesight restored some vision in more than half the volunteers, a study into the fledgling technology has found.

Stem cells derived from embryos "could provide a potentially safe new source of cells for the treatment of various unmet medical disorders requiring tissue repair or replacement", the report's authors said on Tuesday.

The study marks a new chapter in the long story of embryonic stem cells, which after their discovery in the 1990s were hailed as a miracle cure but then ran into problems.

Published in The Lancet, the paper looked at a US trial of stem cells among 18 patients suffering from two tragic, degenerative diseases of the retina.

Nine had a condition called Stargardt's macular dystrophy, a leading cause of juvenile blindness, and nine had dry atrophic age-related macular degeneration, which occurs among the middle-aged and elderly.

There is no conventional treatment for either condition, which eventually leads to complete blindness as the retina's light-receiving cells die out.

The participants were injected with one of three different doses of retinal cells derived from early-stage embryos - 50,000, 100,000 or 150,000 cells.

The transplants were placed in a space under the retina of the worst-affected eye.

The patients were monitored for up to 37 months, for an average of 22 months.

Out of the 18 treated eyes, 10 showed substantial improvements in vision, as measured by the ability to read letters on a board. Of these, eight patients were able to read 15 additional letters in the first year after transplant.

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Stem cells restore sight in new study