A bioengineered retinal implant is safe for use in humans and may be effective in treating vision loss caused by a type of macular degeneration, a progressive blinding disease where no therapeutic options currently exist for advanced stages of the condition. The findings from the phase 1/2a clinical trial (which encompasses two phases of analysis) may pave the way to a potential new therapy for advanced non-neovascular age-related macular degeneration (or NNAMD, also known as "Dry" AMD). NNAMD is associated with loss of the retinal pigment epithelium (RPE), a membrane that nourishes and protects retinal visual cells in the eye. Here, Amir Kashani and colleagues examined the safety and efficacy of a bioengineered retinal implant, which they previously developed and tested in rodents. Their implant is composed of human embryonic stem cells that rest on a material and form a membrane, mimicking the RPE. The authors inserted the implant into the eyes of four subjects with advanced NNAMD and monitored their vision over the course of four months to a year. The implant was well tolerated by all four subjects, who maintained their vision throughout the duration of the study (one even demonstrated an observable improvement in visual acuity). Furthermore, post-operative images revealed stem cells in the implants successfully integrated with the subjects' retinal tissue, and their retinas exhibited anatomical changes consistent with reappearance of the RPE. As a next step, the researchers plan to conduct larger prospective studies to further assess the efficacy of the implant for treating NNAMD in humans.