Lesion-tailored, Fundus-controlled Perimetry in Geographic Atrophy (GA).

The goal of this observational study is to evaluate changes in retinal sensitivity over time in patients with geographic atrophy due to age related macular degeneration who are receiving pegcetacoplan as part of routine clinical care. The study aims to determine whether lesion tailored fundus-controlled perimetry can reliably measure functional changes near areas of atrophy and whether this testing can be implemented in everyday clinic care over 24 months. Participants will undergo repeated vision testing, standard eye imaging, and visual function questionnaires while continuing their prescribed treatment.

Inclusion Criteria: * Age 65-90 years. * Geographic Atrophy (GA) secondary to dry Age-related Macular Degeneration (AMD) in at least one eye with the following criteria: * GA lesion size between 1 and 15 mm² (≈ 0.4 to 6 disc areas) * GA borders must be at least 500 μm from the edge of the 30° × 25° optical coherence tomography (OCT) image frame * No confluent GA extending into peripapillary atrophy * Receiving intravitreal pegcetacoplan per label (at least one injection before screening). * Best-corrected visual acuity (BCVA) of 0.1 - 1.0 logMAR (≈ 20/20 to 20/200 Snellen) * Able to undergo mesopic FCP and required imaging. * Informed consent provided. Exclusion Criteria: * Currently or previously active exudative macular neovascularization in the study eye. * High refractive errors (\> ±5.00 Diopters \[D\] spherical equivalent) and significant astigmatism (\> 2.50 D). * Ocular comorbidities likely to confound sensitivity or imaging (e.g., diabetic retinopathy with macular edema, retinal vein occlusion (RVO), inherited retinal disease, uncontrolled glaucoma). * Media opacity precluding reliable fundus-controlled perimetry (FCP) or imaging (e.g., dense cataract, corneal opacity, vitreous hemorrhage). * Any systemic condition judged likely to compromise participation, follow-up, or data integrity.