Assessing the role of macular pigment optical volume in non-neovascular age-related macular degeneration: associations with rod-mediated dark adaptation and disease progression.

PURPOSE: To characterize macular pigment optical volume (MPOV) across non-neovascular age-related macular degeneration (AMD) stages and in healthy controls, and to explore its associations with dark adaptation (DA) time and long-term AMD progression.

DESIGN

Cross-sectional and longitudinal observation study including patients with non-neovascular AMD (early, intermediate, advanced) per Beckman classification and age-similar controls with no retinal disease. All eyes had good-quality dual-wavelength autofluorescence imaging (Spectralis Investigational MPOD Module).

METHODS

DA was assessed using the AdaptDx® extended protocol (LumiThera, Poulsbo, WA). MPOV was calculated for three concentric circles centered on the fovea at radii of 1°, 2°, and 6°. AMD progression was determined through consultation of follow-up clinical and imaging data. Mixed-effects linear regression models evaluated baseline differences between AMD and control eyes, and across non-neovascular AMD stages. Progression risk was assessed using mixed-effectsCox proportional hazards models adjusted for age, AREDS2 use, lens opacities, and fellow eye status.

RESULTS

Our analysis included 110 AMD eyes (58 patients; median age 72, 56.9% female) and 51 control eyes (26 patients; median age 64, 53.9% female). AMD eyes had significantly higher MPOV than controls when calculated at all eccentricities (1, 2, and 6°, all p<0.01). In controls, higher MPOV at all eccentricities was associated with shorter DA time (p<0.05) - a relationship not observed in AMD eyes. Of 108 AMD eyes with follow-up (median, 53.1 months), 24 eyes (22.9%) progressed to a more advanced stage. Higher MPOV values at all eccentricities were independently associated with increased progression risk (all p<0.05)

CONCLUSIONS

AMD eyes show greater MPOV values than controls, especially in intermediate stages. While MPOV correlated with better DA performance in healthy eyes, this relationship was absent in AMD, suggesting a more complex interaction in diseased retina.