Characteristics of the Retinal Pigment Epithelium in Patients with Albinism using Wide-field Polarization-sensitive Optical Coherence Tomography

Abstract

Purpose: To investigate characteristics of the retinal pigment epithelium (RPE) in patients with albinism by wide-field polarization-sensitive optical coherence tomography (PS-OCT).

Methods: Ten eyes of 5 patients with genetically diagnosed albinism were examined by a novel wide-field PS-OCT system (scan angle of 40x40°), specifically imaging RPE pigmentation, based on the polarization state of backscattered light. Conventional intensity based SD-OCT, FAF and electrooculography (EOG) examinations were performed. Data were analyzed with special focus on pigmentation properties of the RPE, using PS-OCT.

Results: PS-OCT showed significant reduction of depolarization at the RPE level in 3 patients. One patient revealed normal RPE appearance (patient 2), one patient showed minor signs of depigmentation (patient 5). Different genotypes causing albinism were associated with heterogeneous RPE pigmentation. Best-corrected visual acuity (BCVA) in eyes with significant reduction of RPE pigmentation (patient 1, 3 and 4) was lower than in eyes with normal RPE appearance in PS-OCT (mean BCVA=0.23, ±=0.12 of patients 1, 3 and 4 vs. BCVA=0.4 in patient 2). Patient 5 had minor signs of RPE depigmentation, not associated with relatively good BCVA results.

Conclusions: Novel in-vivo RPE specific insights in albinism by a novel wide-field PS-OCT system were described. Reduced depolarization in the RPE of albino eyes found in PS-OCT is a strong indicator that the depolarizing effect of the RPE is melanin-related. The degree of depigmentation of the RPE is possibly associated with reduced functionality. Different genotypes in albinism may be causal for heterogeneous levels of RPE pigmentation.

Keywords: 701 retinal pigment epithelium • 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) • 550 imaging/image analysis: clinical