RESUMO
Purpose: To evaluate frequency and severity of segmentation errors of two spectral-domain optical coherence tomography (SD-OCT) devices and error effect on central macular thickness (CMT) measurements. Materials and Methods: Twenty-seven eyes of 25 patients with neovascular age-related macular degeneration, examined using the Cirrus HD-OCT and Spectralis HRA + OCT, were retrospectively reviewed. Macular cube 512 × 128 and 5-line raster scans were performed with the Cirrus and 512 × 25 volume scans with the Spectralis. Frequency and severity of segmentation errors were compared between scans. Results: Segmentation error frequency was 47.4% (baseline), 40.7% (1 month), 40.7% (2 months), and 48.1% (6 months) for the Cirrus, and 59.3%, 62.2%, 57.8%, and 63.7%, respectively, for the Spectralis, differing significantly between devices at all examinations (P < 0.05), except at baseline. Average error score was 1.21 ± 1.65 (baseline), 0.79 ± 1.18 (1 month), 0.74 ± 1.12 (2 months), and 0.96 ± 1.11 (6 months) for the Cirrus, and 1.73 ± 1.50, 1.54 ± 1.35, 1.38 ± 1.40, and 1.49 ± 1.30, respectively, for the Spectralis, differing significantly at 1 month and 2 months (P < 0.02). Automated and manual CMT measurements by the Spectralis were larger than those by the Cirrus. Conclusions: The Cirrus HD-OCT had a lower frequency and severity of segmentation error than the Spectralis HRA + OCT. SD-OCT error should be considered when evaluating retinal thickness.
RESUMO
PURPOSE: To report the frequency, severity and various types of artifacts associated with spectral-domain optical coherence tomography (SD-OCT) based on macular pathologies. METHODS: Data was collected retrospectively from 116 eyes of 116 subjects. SD-OCT (3D-1000, Topcon Corp., Japan) imaging was performed in 40 healthy eyes, 45 eyes with intraretinal pathology (IRP) and 31 eyes with subretinal pathology (SRP). The scan protocol was 12x6 mm radial scan. The frequency and types of artifacts were investigated in each scan and were analyzed based on macular disease. Additionally, the effect of artifacts on the measurement of macular thickness was studied. RESULTS: Errors occurred in 77 eyes (66.38%). Inner retinal boundary misidentification (IRBM) was the most common error (25.86%), with the frequencies of other types of artifacts being 10.34% for off-center fixation, 15.52% for degraded image and 8.6% for outer retinal boundary misidentification (ORBM). The overall error rate of SD-OCT in the retinal pathology group was much higher than that in the normal group. Macular thickness was underestimated in the IRP group because the outer retinal boundary of the IRP group tended to be misidentified toward the inner retina (p<0.01). CONCLUSIONS: SD-OCT can frequently cause various types of artifacts in patients with macular disease. When interpreting OCT images, the artifacts of SD-OCT should be considered in order to obtain accurate macular thickness and to prevent erroneous clinical decisions.