The Optical Coherence Tomography and Microperimetry Biomarker Evaluation in Patients with Geographic Atrophy (OMEGA) Study: Design and Baseline Characteristics (OMEGA report 1)

Introduction: The aim of this study is to describe the design and the participants' baseline characteristics of a prospective natural-history study of geographic atrophy (GA) secondary to age-related macular degeneration.Methods: The optical coherence tomography (OCT) and microperimetry biomarker evaluation in patients with GA (OMEGA) study was conducted at a tertiary referral center (ClinicalTrials.gov identifier: NCT05963646). Participants were followed for 12 months during 4 visits (baseline and follow-up exams at weeks 12, 24, and 48) with best-corrected ETDRS visual acuity, low-luminance visual acuity, and quick contrast sensitivity function (qCSF) testing. Further, participants underwent spectral-domain OCT, OCT angiography, fundus autofluorescence (FAF) imaging, and mesopic microperimetry testing.Results: Thirty participants (median [IQR] age of 79 [77, 84] years) and 37 study eyes were included with a (median [IQR]) GA area of 1.40 mm(2) [0.49, 5.24] at baseline. Out of 37 study eyes, six developed macular neovascularizations (16%). The study-eye BCVA was (median [IQR]) 0.18 logMAR [0.06, 0.26], LLVA 0.66 logMAR [0.36, 0.88], and the microperimetry mean sensitivity 18.4 dB [9.21, 20.9]. The highest correlation between square root GA area and a visual function test was evident for LLVA (R-2 of 0.578), followed by AULCSF (0.519) and microperimetral retinal sensitivity (0.487).Conclusion: This report lays out the design and baseline characteristics of the OMEGA study, which aims to contribute to the understanding of the natural history of GA. The OMEGA study will provide estimates of the ability-to-detect change and retest reliability for a panel of structure and function assessments.