Adaptive Optics Scanning Light Ophthalmoscopy (AOSLO) and Microperimetry (MP) Sub-study

Inclusion Criteria (from the main study): * 50 years or older and may be either male or female and may be of any race * Established diagnosis of geographic atrophy (GA) due to age-related macular degeneration (AMD) * GA characteristics: GA area of between 1.25 mm² and 23 mm², with seventy percent of eyes having GA area ranging from 2.5 mm² to 17.5 mm². GA may be unifocal or multifocal. GA may be subfoveal or extrafoveal, with twenty-five percent of eyes having subfoveal GA. The presence of concurrent peripapillary atrophy will not exclude participants from participation * Willing to participate as evidenced by signing the written informed consent Additional Sub-study Inclusion Criteria: * Early-stage GA defined as * GA area of between 1.25 mm2 and 23 mm2 * GA may be unifocal or multifocal * GA may be subfoveal or extrafoveal * Concurrent peripapillary atrophy will not exclude participant from participation * Phakic and pseudophakic participants are eligible for enrollment, with phakic participants prioritized when feasible. Exclusion Criteria (from the main study): * Unable to tolerate ophthalmic imaging * Presence of neovascular AMD on optical coherence tomography (OCT) as confirmed by an ophthalmologist * Presence of significant media opacity preventing adequate retinal imaging * Presence of concurrent retinal disease which may confound assessment Additional Sub-study Exclusion Criteria: * Ocular media opacity or other condition(s) that, in the opinion of …