Evaluating the Relationship Between Function and Structure Using Data From a GA Natural History Cohort

Overview

Geographic atrophy (GA) is an advanced form of dry age-related macular degeneration that leads to progressive and irreversible vision loss. The course of visual decline varies widely among patients, and it is not always clear which anatomical features of the retina are associated with faster loss of vision. This retrospective observational study aims to describe the natural history of vision loss in patients with geographic atrophy who have characteristics similar to those enrolled in recent clinical trials. The study will analyze previously collected clinical and imaging data from patients followed during routine clinical care at a single center. The main goal of the study is to evaluate the relationship between changes in visual function and retinal anatomical features, such as the size and location of atrophic lesions and retinal layer integrity, using fundus autofluorescence and optical coherence tomography images. No treatments or study procedures are performed as part of this research. All data used in the study were collected during standard clinical practice and analyzed retrospectively.

This is a monocentric, retrospective observational study designed to evaluate the relationship between visual function and retinal anatomical features in a population with geographic atrophy (GA) secondary to dry age-related macular degeneration. The study will analyze a natural history cohort identified from previously collected clinical and imaging data obtained during routine care at IRCCS Ospedale San Raffaele. Eligible eyes meet predefined inclusion and exclusion criteria consistent with those used in recent clinical trials, including well-demarcated GA lesions, preserved baseline visual acuity, and the absence of choroidal neovascularization or prior intravitreal treatment. The primary objective is to estimate the proportion of eyes experiencing a loss of at least 15 ETDRS letters from baseline and to characterize the trajectory of visual acuity decline over time. Secondary objectives include the identification of baseline anatomical features associated with the risk and timing of significant visual loss, such as GA lesion size, foveal involvement, fundus autofluorescence patterns, lesion focality, and outer retinal layer thickness measured on optical coherence tomography. Exploratory analyses will investigate the relationship between visual function decline and ellipsoid zone integrity metrics, where available, and will apply multivariable and machine learning-based models to explore non-linear associations between anatomical and functional parameters. As this is a retrospective study, no investigational medicinal products, devices, or study-specific interventions are involved. All analyses are performed on pseudonymized or anonymized data derived from existing medical records and imaging archives. No additional patient contact, visits, or procedures are required.