The relationship between central drusen volume and low-luminance deficit in age-related macular degeneration

Abstract

Purpose: To determine the relationship between central drusen volume and low-luminance deficit (LLD) in visual acuity (VA) in patients with intermediate age-related macular degeneration (AMD). Methods: In this cross-sectional study, 42 patients with intermediate AMD underwent testing for VA and low-luminance VA (LLVA), as well as spectral-domain optical coherence tomography. LLD was calculated as the difference between VA and LLVA. Central drusen volume was measured in the central 3 mm of the macula, defined as the volume between the inner border of the retinal pigment epithelium and Bruch’s membrane. Results: Mean ± standard deviation (SD) LLD was 0.32 ± 0.12 logMAR and mean ± SD drusen volume was 0.18 ± 0.09 mm3 . No linear relationship was identified between central 3 mm drusen volume and LLD (P = 0.215). R2 for the bivariate linear model was 0.038 (95% confidence interval 0–0.222). Limitation of the analysis to drusen volumes measured in the central 1 mm of the macula did not impact results (R2 = 0.075), nor did incorporation of lens status into the model (R2 = 0.067) or censoring of patients with nonfoveal subretinal drusenoid deposits (R2 = 0.071). Conclusions: The amount of drusen within the central 3 mm of the macula does not appear to be related to LLD in intermediate AMD. These measures may be manifestations of different underlying pathophysiological mechanisms. Translational Relevance: Understanding relationships between markers for AMD progression may help guide development of improved clinical grading scales for AMD.