Advances in Photoreceptor and Retinal pigment epithelium Quantifications in intermediate AMD: High-Res versus Standard SPECTRALIS OCT

Abstract

Purpose: In this study we investigated differences in retinal feature visualization of high-resolution optical coherence tomography (OCT) devices with different axial resolutions in quantifications of retinal pigment epithelium (RPE) and photoreceptors (PR) in intermediate age-related macular degeneration (iAMD). Methods: Patients were imaged with standard SPECTRALIS HRA+OCT and the investigational High-Res OCT device (both by Heidelberg Engineering, Heidelberg, Germany). Drusen, RPE and PR layers were segmented using validated AI-based algorithms followed by manual corrections. Thickness- and drusen maps were computed for all patients. Loss and thickness measurements were compared between devices, drusen vs. non-drusen areas and EDTRS subfields using mixed-effects models. Results: Thirty-three eyes from 28 iAMD patients were included. Normalized PR integrity loss was significantly higher with 4.6% for standard OCT compared to 2.5% on High-Res OCT. The central and parafoveal PR integrity loss was larger than perifoveal loss (p<0.05). PR thickness was increased on High-Res OCT and in non-drusen regions (p<0.001). RPE appeared thicker on standard OCT and above drusen (p<0.01). Conclusion: Our study shows that High-Res OCT is able to identify the condition of investigated layers in iAMD with higher precision. This improved in vivo imaging technology might promote our understanding of the pathophysiology and progression of AMD.