Purpose
To identify the biologic response of the retinal pigment epithelium (RPE) to antiangiogenic therapy for neovascular age-related macular degeneration (AMD) using selective RPE imaging by polarization-sensitive optical coherence tomography (PS-OCT).
Methods
Thirty patients (31 eyes) with treatment-naïve neovascular AMD treated with intravitreal Ranibizumab were included in this study. Patients were examined by SD- (spectral domain) and PS-OCT (capable of specifically detecting the RPE and associated changes) prior to anti-VEGF therapy (baseline), 1, 3, 6, 12 and 24 months postoperatively, focusing on RPE characteristics in PS-OCT. Geographic atrophy (GA) dimensions were evaluated using an automated segmentation algorithm in PS-OCT. SD- and PS-OCT results were compared.
Results
Atrophic RPE changes were evident in PS-OCT during follow-up including: RPE thinning, RPE porosity, focal RPE atrophy, advanced GA. Increased RPE density was identifiable in certain cases, presumably following RPE migration and/or proliferation. Such reactive changes affecting the regenerative potential of the RPE such as RPE migration, RPE thickening, accumulations of depolarizing material at the RPE level increased initially and then decreased during long-term follow-up. GA dimensions in PS-OCT were detected in 19 patients at month 24 with a mean area of 1.10mm2 (±1.09). PS-OCT unambiguously identified the RPE layer while conventional intensity-based SD-OCT failed to detect RPE changes qualitatively and quantitatively.
Conclusions
Characteristic and dynamic changes of the RPE layer were shown in patients undergoing antiangiogenic therapy for neovascular AMD using RPE-specific imaging by PS-OCT. RPE loss and RPE atrophy increased generally with GA progression becoming evident following 24 months of follow-up. RPE-selective imaging is required to identify biologic changes of the RPE associated with anti-angiogenic therapy.
Keywords: 552 imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound) •
550 imaging/image analysis: clinical •
701 retinal pigment epithelium