Evaluation of intraretinal migration of retinal pigment epithelium in age-related macular degeneration by polarization sensitive SLO and OCT

Abstract

Purpose : We hypothesized that depolarization in polarimetry imaging is useful to evaluate the retinal pigment epithelium (RPE). In this study, we evaluated the intraretinal migration of RPE in age-related macular degeneration (AMD) using polarimetry methods

Methods : We prospectively examined 110 eyes of 84 patients with AMD, including 14 eyes of early AMD, 22 eyes of serous retinal pigment epithelial detachment (PED), 17 eyes of remission stage of exudative AMD, 49 eyes of end stage of exudative AMD with fibrotic scar, and 8 eyes of dry AMD with geographic atrophy. Depolarized light images were computed using a polarization-sensitive scanning laser ophthalmoscope (PS-SLO) at 780 nm. To obtain polarimetry information with improved axial resolution, we calculated the Makita's degree of polarization uniformity (M-DOPU) from the data set obtained by a Jones-matrix polarization-sensitive swept-source optical coherence tomography (OCT) with 1-μm probing wavelength. Melanin-containing structures like RPE are source of depolarization, and induce low M-DOPU in PS-OCT and depolarization in PS-SLO. Each polarimetry image was compared with auto-fluorescence image at 500 nm (SW-AF) and 800 nm (NIR-AF). Intraretinal RPE migration was defined by the presence of low M-DOPU in PS-OCT at intraretinal hyper-reflective foci in standard OCT, and hyper-AF in both NIR-AF and SW-AF images at corresponding location.

Results : Intraretinal RPE migrations were detected in 45 of 110 eyes (41%) [5 of 14 eyes with early AMD (36 %), 18 of 22 eyes with PED (82 %), 8 of 17 eyes with remission stage (47 %), 11 of 49 eyes with end stage (22 %), and 3 of 8 eyes with dry AMD (38 %)]. Intraretinal RPE migrations were observed in PED with significantly higher frequency than other groups (P = 0.04). Numerous RPE migrations were observed in 10 eyes with PED. PS-SLO showed depolarization at corresponding location to intraretrinal RPE migration, and showed similar feature to NIR-AF images. Findings at intraretrinal RPE migration in NIR-AF and PS-SLO were clearer than SW-AF.

Conclusions : Intraretinal RPE migration occur in the various stage of AMD, and occur more commonly in the eyes with PED. Polarimetric imaging is useful to evaluate intraretinal RPE migration in AMD.

This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.

 

Multiple intraretinal RPE migration in an eye with PED