(NBC) - Preliminary research suggests the use of embryonic stem cells may improve sight in patients with degenerative vision loss.
Scientists at UCLA transformed embryonic stem cells into pigmented retinal cells, which were implanted into one eye of 18 patients.
Eight of the 18 eyes that underwent the procedure had significantly better vision after several years while there was no change in the untreated eyes.
Pigment levels also increased in 13 eyes - but that did not necessarily improve sight.
Critics of the study say vision improvements could be due to the procedure itself, rather than the transplanted cells.
This trial is one of only a few involving human embryonic stem cells.