Probably several years. They've only had a small scale human trial of 12 patients so far, and a larger scale human trial is likely to take some time to organize, then of course the post-trial monitoring for possible side effects will need to continue for some time, probably 24-36 months.
Everyone hopes of course that these patients will enjoy permanently repaired vision, but there's no way to know for a long time. Also, stem cells have an unfortunate tendency to turn into cancer. The field is really still in its infancy, but the potential is enormous.
