Abstract
Purpose:
To compare retinal pigment epithelium (RPE) and retinal thickness assessments made with SDOCTin eyes with dry AMD and normal eyes.
Methods:
Eyes with intermediate AMD or worse in participants between 50 - 85 years of age were evaluated in custom SDOCT segmentation software. After converting to a standardized Digital Imaging and Communications in Medicine (DICOM) format, macular volume scan files from 4 different SDOCT machines were displayed in the same software and segmented for inner limiting membrane (ILM), RPE-drusen complex and Bruch’s membrane (BM) in a display and analysis platform using an algorithm developed at the University of Wisconsin’s Fundus Photograph Reading Center (Huang, et al, PLoS One. 2013 Dec 26;8(12):e82922) (Fig 1 top). Reading center graders reviewed each volume scan and edited boundary line placement if required. Similar segmentation (ILM, RPE and BM - Fig 1 bottom) was performed in SDOCT scans from participants of same age range in whom dry AMD and other confounding abnormalities had been ruled out.
Results:
The mean central subfield (CSF) retinal thickness was significantly different between eyes with dry AMD (n = 72) and normal eyes (n= 435); 225.8µ (SD 39.8) and 245.5µ (SD 27.8) respectively. Total retinal volume was also significantly different between the two groups; 7.4mm3(0.5) and 7.6 mm3 (0.5) respectively. In the central subfield, thickness of the RPE-drusen complex was 70.8 µ (SD 31.6) and RPE thickness in normal eyes was 33.3 µ (SD 4.6) (P<0.001). The RPE-drusen complex volume and RPE volume was also significantly different between the two groups; 1.1 mm3 (SD 0.2) and 0.8 mm3 (SD 0.1).
Conclusions:
Drusen segmentation can be effectively performed in eyes with dry AMD and can be used as an outcome for clinical trials. Regression in drusen volume towards normal can potentially be identified using custom segmentation.