Quantitative comparison of macular segmentation performance using identical retinal regions across multiple spectral-domain optical coherence tomography instruments.

PURPOSE: Comparison of optical coherence tomography (OCT) segmentation performance regarding technical accuracy and clinical relevance.
METHODS: 29 eyes were imaged prospectively with Spectralis (Sp), Cirrus (Ci), 3D-OCT 2000 (3D) and RS-3000 (RS) OCTs. Raw data were evaluated in validated custom software. A 1 mm diameter subfield, centred on the fovea, was investigated to compare identical regions for each case. Segmentation errors were corrected on each B-scan enclosed in this subfield. Proportions of wrongly segmented A-scans were noted for inner and outer retinal boundaries. Centre point thickness (CPT) and central macular thickness (CMT) were compared before and after correction.
RESULTS: Segmentation errors occurred in 77% and affected on average 29% of A-scans, resulting in mean differences of 24/13 µm (CPT/CMT). The incidence of segmentation errors was 48% (Sp), 79% (Ci), 86% (3D) and 93% (RS), p<0.001. Mean proportions of A-scans with wrong outer retinal boundary were 30% (Sp), 9% (Ci), 23% (3D) and 10% (RS), p=0.006; proportions for the inner retinal boundary were 11% (Sp), 12% (Ci), 6% (3D) and 21% (RS), p=0.034. Mean deviations in CPT/CMT were 41/28 µm (Sp), 17/11 µm (Ci), 30/13 µm (3D) and 18/8 µm (RS), p=0.409/0.477.
CONCLUSIONS: By comparison of identical regions, substantial differences were detected between the tested OCT devices regarding technical accuracy and clinical impact. Spectralis showed lowest error incidence but highest error impact. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.