Reticular Pseudodrusen: Impact of their Presence and Extent on Local Rod Function in Age-Related Macular Degeneration

Purpose To understand the spatial relationship between local rod-mediated visual function and reticular pseudodrusen (RPD) in eyes with large drusen. Design Retrospective cross-sectional study. Participants One eye with large drusen (>125μm) each from 91 individuals with intermediate age-related macular degeneration (AMD), with and without RPD. Methods All participants underwent dark adaptation testing using a dark-adapted chromatic perimeter, where visual sensitivities were measured over 30 minutes of dark adaptation following photobleach. The rod intercept time (RIT; a measure of dynamic rod function) and pointwise sensitivity difference (PWSD; a relative measure of rod- compared to cone-mediated function) was determined at multiple retinal locations, and their association with the overall (central 20ºx20º region) and local (2º diameter region centered on the location tested) extent of RPD and drusen (quantified using multimodal imaging) was examined. Main Outcome Measure Association between overall and local extent of RPD and drusen with RIT and PWSD at each retinal location tested. Results In a multivariable analysis, delayed RIT was associated with an increasing overall (P<0.001), but not local (P=0.884), extent of RPD. In contrast, the increasing local (P<0.001), but not overall (P=0.475), extent of drusen was associated with delayed RIT. Furthermore, only an increasing overall extent of RPD (P<0.001) was associated with reduced PWSD (or worse rod compared to cone function), but not the local extent of RPD and drusen, or overall extent of drusen (P≥0.344). Conclusions Local rod-mediated function was associated with the overall, rather than local, extent of RPD in eyes with large drusen, suggesting that there may be widespread pathological changes in eyes with RPD that account for this.