Maximum reading speed in patients with geographic atrophy secondary to age-related macular degeneration

PURPOSE. Geographic atrophy (GA) is an advanced form of age-related macular degeneration. GA often initially spares the center of the fovea, leading to a functional disconnect between reading speed and distance visual acuity. This study was designed to determine the correlation between baseline GA lesion size, change in lesion size, and maximum reading speed (MRS) over 18 months. METHODS. Post hoc analysis included US patients from the phase 2 Mahalo study of intravitreal lampalizumab with Minnesota low-vision reading (MNREAD) assessments at baseline and 6, 12, and 18 months. Binocular MRS was assessed using MNREAD Acuity Charts and GA lesion size by fundus autofluorescence. Correlations were estimated using Spearman’s rank correlation coefficient. RESULTS. Seventy-seven patients were included in the analysis. Baseline MRS correlated with baseline GA lesion size (correlation coefficient, 0.47; 95% confidence interval, 0.63 to 0.28; P < 0.0001). In patients with lesions ≥10 mm² (four disc areas), the proportion reading below a nonfluent level (MRS, <40 words/min) at baseline (26.5%) increased to 64.7% by 18 months, versus patients with lesions <10 mm² (baseline, 9.3%; 18 months, 7.0%). MRS declined by a median of 40.9% (interquartile range [IQR], 70.2 to 6.9) in patients with ≥2.5 mm² lesion growth versus 8.2% (IQR, 34.6 to 11.0) in patients with <2.5 mm² lesion growth from baseline to 18 months. CONCLUSIONS. These findings suggest that baseline GA lesion size and magnitude of lesion growth are associated with a decline in MRS over time and support the use of MRS as an evaluation of functional vision in patients with GA.