The Relationship Between Central Drusen Volume and Low-Luminance Deficit in Age-Related Macular Degeneration

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).

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.

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).

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.

Understanding relationships between markers for AMD progression may help guide development of improved clinical grading scales for AMD.