A Study to Optimize Subretinal Surgical Delivery and to Evaluate Safety and Activity of Opregen in Participants With Geographic Atrophy Secondary to Age-Related Macular Degeneration (GAlette); Adaptive Optics (AO) Retinal Imaging Substudy in Association With Study GR44251

This study is evaluating a cell therapy called OpRegen for people with geographic atrophy (GA), a severe form of age-related macular degeneration (AMD) that causes gradual, permanent central vision loss. OpRegen uses retinal pigment epithelium cells grown from stem cells and delivered surgically beneath the retina to replace the dying cells responsible for this condition. The study also includes an optional sub-study using advanced imaging technology called adaptive optics to closely monitor changes in the retina. You may be eligible if: - You are 50 years of age or older - You have been diagnosed with geographic atrophy caused by AMD - Your best corrected vision in the study eye falls within a specific range (29–60 ETDRS letters) - The lens in your study eye has already been replaced (pseudophakic) - You are able to undergo eye surgery under monitored anesthesia You may NOT be eligible if: - You are pregnant or breastfeeding - You have a history of cognitive impairment or dementia - You have a serious or progressive systemic illness - You have any other eye disease affecting the central retina - You have had a retinal detachment, vitrectomy, or glaucoma surgery in the study eye - You have uncontrolled or advanced glaucoma - You have had cataract surgery or eye surgery within 3 months of this procedure - You have had a prior seizure (except a single childhood febrile seizure) — for the sub-study Talk to your doctor to see if this trial is right for you.