gms | German Medical Science

Purpose: To describe the distinct courses of geographic atrophy (GA) progression in GA secondary to Age related macular degeneration (AMD) and late onset Stargardt disease (LO-STGD).

Methods: Patients were recruited from the prospective natural history Fundus-Autofluorescence imaging in Age-related Macular Degeneration study (FAM, NCT00393692) and the Departments of Ophthalmology of the University of Nijmegen and the University of Bonn. Longitudinal examinations with fundus autofluorescence (FAF) and near-infrared reflectance (IR) imaging (Spectralis HRA+OCT or HRA2, Heidelberg Engineering) were performed. Areas of GA were quantified using a semi-automated software tool (RegionFinder, Heidelberg Engineering). Rates of GA progression were calculated and compared using a linear mixed-model (LMEM) approach.

Results: A total of 226 eyes (151 patients) with GA secondary to AMD and 59 eyes (36 patients) with GA secondary to late-onset Stargardt disease were examined longitudinally over 2.8 years (±1.98 years). Mean age at baseline was 74.02±7.44 years in the AMD and 63.62±10.38 years in the LO-STGD patients cohort (p<0.001). At first presentation GA size was 6.30 ± 4.99 mm² in AMD and 5.87 ± 6.87 mm² in LO-STGD eyes (p=0.5). Applying the LMEM revealed that square root atrophy progression was significantly faster in AMD patients than in LO-STGD patients (0.26 ±0.01 mm/y vs. 0.20 ±0.03 mm/y, p=0.026).

Conclusions: GA progression rate is significantly slower in eyes with late-onset Stargardt disease as compared to those with AMD. These natural history data underline the relevance of refined phenotypeing in elderly patients presenting with GA and contribute to the design of future interventional trials.