Evaluation of focal damage of retinal pigment epithelium layer in retinal pigment epithelium detachment by polarization sensitive optical coherence tomography

Abstract

Purpose : We hypothesized that depolarization in polarimetry imaging is useful to evaluate the retinal pigment epithelium (RPE). In this study, we evaluated the focal damage of RPE layer in RPE detachment (PED) using polarization sensitive optical coherence tomography (PS-OCT).

Methods : We prospectively examined 54 eyes of 47 patients with PED in age-related macular degeneration, including 35 eyes of serous PED and 19 eyes of drusenoid PED. Degree of polarization uniformity (DOPU) was calculated from the data set of PS-OCT with 1-μm probing wavelength. Melanin-containing structures like RPE are source of depolarization, and induce low DOPU in PS-OCT. Each PS-OCT image was compared with auto-fluorescence image at 480 nm (SW-AF) and 780 nm (NIR-AF). Focal RPE damage was defined by the presence of focal defect of depolarization in PS-OCT image at RPE-basal lamina band without RPE tear, hyper-transmission below the RPE line in standard OCT images, and hypo-AF in SW-AF and NIR-AF images at corresponding location. Volumes of PED and intraretinal hyper-reflective foci (HRF) were calculated using standard OCT images, and compared with the existence of focal RPE damage

Results : Focal RPE damages were detected in 22 of 54 eyes (41 %) [14 of 35 eyes (40 %) in serous PED and 8 of 19 eyes (42%) in drusenoid PED]. Among them, standard OCT images did not show obvious change in RPE-basal lamina band at focal RPE damage in 18 of 22 eyes (82 %) [12 of 14 eyes (86 %) in serous PED and 6 of 8 eyes (75 %) in drusenoid PED]. PED volume did not show any significant differences by the presence of focal RPE damage. In serous PED group, HRF volume in the eyes with focal RPE damage (mean: 0.0070 mm³) was significantly larger than the eyes without focal RPE damage (mean: 0.0020 mm³) (P = 0.009). Presence of RPE migrations at these HRF were confirmed by low DOPU in PS-OCT, and hyper-AF in both NIR-AF and SW-AF images at corresponding location.

Conclusions : PS-OCT is more sensitive than standard OCT for detection of focal RPE damage. In serous PED, the development of focal RPE damage is related with intraretinal RPE migration.

This is an abstract that was submitted for the 2018 ARVO Annual Meeting, held in Honolulu, Hawaii, April 29 - May 3, 2018.

 

Focal RPE damage with intraretinal RPE migration. White arrows indicate the defect of depolarization in PS-OCT image at RPE-basal lamina band, and hypo-AF in both NIR-AF and SW-AF images at corresponding location.