Intraretinal Retinal Pigment Epithelium Cells in Age-Related Macular Degeneration.

Purpose: To examine intraretinally migrated retinal pigment epithelium cells (iRPECs) in enucleated human eyes with various retinal conditions and corresponding intraretinal hyperreflective bodies (iHRBs) in a large cohort of patients with age-related macular degeneration (AMD) in China. Design: Population-based study and histomorphometric investigation. Participants: Participants of the population-based Beijing Eye Study and enucleated human eyes. Methods: OCT-based and fundus photography-based examination of the macula of the Beijing Eye Study participants and light-microscopical histomorphometry of enucleated human eyes. Main Outcome Measures: Presence and location of iRPECs and iHRBs. Results: In the Beijing Eye Study (6551 eyes; 3301 participants), the prevalence of intermediate AMD and late AMD was 331 (5.1%) and 44 (0.6%), respectively. All 42 eyes with intermediate AMD and macular hyperpigmentation had iHRBs at locations corresponding spatially with macular hyperpigmentation on the fundus photographs. Among all eyes with intermediate AMD (n = 331), iHRBs were detected in 262 (79.2%) eyes. The most internal location of the iHRBs was at the ellipsoid zone in 46 (13.9%) eyes, at the external limiting membrane (ELM) in 45 (13.6%) eyes, and in the outer nuclear layer in 145 (43.8%) eyes. Out of the 262 eyes with iHRBs, 186 (71.0%) eyes showed a corresponding defect in the ellipsoid zone, and 128 (48.9%) eyes showed a defect in the ELM. The eyes with an iHRB located beneath the ELM did not show an ELM defect. The iHRBs were associated with a plume-like appearance and with a smoke-like appearance in 20 (7.6%) eyes and 137 (52.3%) eyes, respectively. All iHRBs did not have a shadow on the OCT images. Similar findings were obtained in the eyes with late AMD. Among 237 eyes examined histologically, 21 globes showed iRPECs: 8 eyes in parapapillary α zone/β zone; 5 eyes with myopic patchy atrophies, and 3 eyes with AMD. The iRPECs were spatially associated with an ELM defect and were not surrounded by a basal membrane. Conclusions: Intraretinal hyperreflective bodies can be found in 3 out of 4 eyes with intermediate AMD, correlate histologically with intraretinally located (migrated) retinal pigment epithelium cells, and correspond spatially with localized defects of the ellipsoid zone and ELM. Financial Disclosures: Proprietary or commercial disclosure may be found in the Footnotes and Disclosures at the end of this article.