Topographic Rod Recovery Profiles after a Prolonged Dark Adaptation in Subjects with Reticular Pseudodrusen

Chi D Luu; Rose Tan; Emily Caruso; Erica L Fletcher; Trevor D Lamb; Robyn H Guymer

doi:10.1016/j.oret.2018.06.016

Topographic Rod Recovery Profiles after a Prolonged Dark Adaptation in Subjects with Reticular Pseudodrusen

Ophthalmol Retina. 2018 Dec;2(12):1206-1217. doi: 10.1016/j.oret.2018.06.016. Epub 2018 Aug 18.

Authors

Chi D Luu¹, Rose Tan², Emily Caruso², Erica L Fletcher³, Trevor D Lamb⁴, Robyn H Guymer²

Affiliations

¹ Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Department of Surgery (Ophthalmology), The University of Melbourne, East Melbourne, Victoria, Australia. Electronic address: cluu@unimelb.edu.au.
² Centre for Eye Research Australia, Royal Victorian Eye and Ear Hospital, Department of Surgery (Ophthalmology), The University of Melbourne, East Melbourne, Victoria, Australia.
³ Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, Victoria, Australia.
⁴ Eccles Institute of Neuroscience, John Curtin School of Medical Research, The Australian National University, Canberra, ACT, Australia.

PMID: 31047193
DOI: 10.1016/j.oret.2018.06.016

Abstract

Purpose: Although rod function is known to be severely impaired in eyes with reticular pseudodrusen (RPD), it remains unknown whether this impairment is associated with a total loss of rod function or merely a delay in rod recovery. The purpose of the study was to determine rod functional recovery profiles after prolonged dark adaptation (DA) in eyes with age-related macular degeneration (AMD) and RPD.

Design: A cross-sectional, case-series study.

Participants: Subjects with AMD and RPD.

Methods: Retinal sensitivity was assessed simultaneously at 14 retinal locations within the central 12° in the study eye of each subject after the eye received approximately 20% bleach. Recovery of retinal sensitivity was monitored at regular intervals up to 30 minutes after bleach. If retinal sensitivity of all test points had not recovered to the rod criterion level (-3.0 log units of stimulus intensity) after 30 minutes of DA, monitoring recovery of retinal sensitivity was extended up to 24 hours of DA.

Main outcome measures: Rod functional recovery profile at each test point.

Results: Six AMD cases with RPD were included, aged 69 to 79 years, and visual acuity ranged from 20/20 to 20/25. All cases had a delay in rod functional recovery at many retinal locations, with test points within the central 6° most affected. The recovery rate was variable between retinal loci and between subjects, although RPD were present at all test locations. In 5 cases with stage 3 RPD, rod function recovered at all tested locations, but many locations took hours to do so. The case with stage 4 RPD had locations that failed to recover even after 24 hours of DA.

Conclusions: Eyes with AMD and RPD are associated with severe rod dysfunction throughout the macula; however, rod function does recover in most cases after an extended DA time. These findings suggest that the delay in rod recovery in eyes with RPD is, in most cases, associated with the impairment rather than the total loss of rod photoreceptor function. Stage 4 RPD may represent a point at which some rod photoreceptors are nonfunctional.