Outer Retinal Hyperreflective Dots: A Potential Imaging Biomarker in Rhegmatogenous Retinal Detachment

Abstract

To investigate hyperreflective dots (HRDs) on baseline OCT in rhegmatogenous retinal detachment (RRD). Retrospective cohort study. Consecutive primary fovea-off RRDs presenting between January 2012 and September2022. Visual acuity (VA) was obtained at baseline, 3, 6, and 12 months. Baseline foveal OCT scans were graded for the presence of HRDs in the outer retina, morphologic stage of RRD in the parafovea, and foveal photoreceptor integrity (intact, patchy or complete loss of the bacillary layer). Epiretinal membrane (ERM) and cystoid macular edema (CME) were graded after surgery. The primary outcome was the proportion of patients in each morphologic stage with HRDs present on OCT and their association with postoperative VA. Secondary outcomes included association with the height of foveal detachment, duration of central vision loss, RRD extent, and development of ERM/CME. A total of 351 patients were included. The presence of HRDs by morphologic stage of RRD was 0% in stage 1, 4.5% (2/42) in stage 2, 13% (7/54) in stage 3a, 16% (20/126) in stage 3b, 48% (40/83) in stage 4, and 85% (35/41) in stage 5. Hyperreflective dots were associated with increasing stage of RRD (P < 0.001), reduced integrity of foveal photoreceptors (P < 0.001), and reduced postoperative VA at 3, 6, and 12 months (P < 0.001), after excluding visually significant cataracts and adjusting for covariates. There was also a significant association between HRDs and height of foveal detachment, duration of central vision loss, and RRD extent (P< 0.001). Hyperreflective dots were neither associated with postoperative ERM formation nor with its severity(P= 0.27). Nevertheless, they were associated with the occurrence of CME at 3 and 6 months after surgery (P= 0.01; P= 0.006). Hyperreflective dots have been hypothesized to consist of intraretinal inflammatory cells. We found that HRDs were significantly associated with the morphologic stage, extent, duration, and height of the RRD before surgery and with reduced VA and CME after surgery. Our results suggest that HRDs are associated with photoreceptor degeneration, as longstanding and extensive RRDs are more likely to present with HRDs. The association of HRDs with CME provides insight into the possible importance of inflammatory processes in RRD before and after surgery. The author(s) have no proprietary or commercial interest in any materials discussed in this article.