Sixteen years ago the isolation of embryonic stem cells was said to be the foundation for a future of interchangeable body parts—when a liver failed you would just grow a new one. These predictions seemed pretty close to science fiction, but a recent study has shown that this could soon be science fact. In one of the most extensive studies on the use of stem cells to date, scientists have successfully used stem cells to treat eye disease. The study turned stem cells into retinal cells—that help the eye pick up light—and successfully implanted them in patients. The study was made up of 18 patients and followed them for about 22 months. While only 8 of the 18 treated eyes could see better after the procedure, this discovery could mean a much brighter world is coming for those suffering from eye disease.