Abstract
Purpose :
Reticular pseudodrusen (RPD) are dynamic lesions that have been observed in the early stages of many diseases, including age-related macular degeneration and late-onset retinal degeneration (L-ORD). This study aims to quantify the extent of damage to the cells affected by the onset and progression of RPD using multimodal adaptive optics (AO) retinal imaging: confocal and split detection modalities to assess cone photoreceptors, and AO-enhanced indocyanine green (AO-ICG) imaging to assess the retinal pigment epithelium (RPE).
Methods :
Longitudinal adaptive optics imaging was performed in both eyes of a 56-year-old patient with L-ORD (S163R mutation in C1QTNF5) over two visits spaced 8 months apart. Using confocal AO imaging, the RPD lesions were classified into five categories: new, growing, stable, shrinking, and disappearing, based on the intervisit change in size of their hyperreflective cores. For both visits, cone photoreceptor inner segment effective diameters were measured at sites of RPD lesions and then compared between lesion categories. The RPE underlying the RPD was assessed using AO-ICG during the second visit.
Results :
Out of a total of 118 RPD lesions from both eyes, 48% were observed to be shrinking or disappearing, 32% growing or appearing, and 20% stable across the two visits. The percentage of RPD lesions in each RPD lesion category did not significantly change with eccentricity from the fovea. Defects in the RPE were observed using AO-ICG beneath 45% of RPD lesions. Of the RPD lesions that showed RPE defects, there was no apparent relationship between the size of the RPE defect and visit to visit area change of the RPD lesion, suggesting that RPE defects can occur at any point throughout the lifecycle of RPD. In contrast, we observed that cone photoreceptor swelling occurs at the timepoint when the hyperreflective RPD core is formed (i.e. new RPD category) with an average effective diameter increase of 47.5% (p<0.001). Following the initial swelling, there was no recovery of cone diameter even in the cases of RPD lesion resolution (i.e. RPD disappearing category).
Conclusions :
Multimodal AO imaging reveals that cone photoreceptors become swollen upon formation of the RPD hyperreflective core with no recovery in size in areas of disappearing RPD lesions. In contrast, RPE defects occur across all RPD lesion categories.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.