A new study published in Lancet on Tuesday presents the first strong evidence that human embryonic stem cells are helping patients. Human embryonic stem cells, which can become any cell in the body, have long been thought of as a source for replacement tissue. In this study, stem cells were transformed into retinal pigment epithelium cells, and then injected into one eye of patients going blind. After injection, the patients were followed for an average of 22 months, and two of them for over three years. While the study was mostly designed to see if the treatment was safe, many of the patients were pleasantly surprised that their vision improved due to treatment. In fact, vision improved by what is considered to be a significant amount in eight of the eighteen treated eyes. The scientists caution though that this work is in its early stages, but are expanding the trial and following more patients.

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