Identifying the boundaries of retinal pigment epithelial detachments using two spectral-domain optical coherence tomography instruments

Abstract

Background and objective: To compare two spectral-domain optical coherence tomography (SD-OCT) instruments in identifying the boundaries of retinal pigment epithelium detachment (PED).

Patients and methods: 27 eyes were scanned with Cirrus and Spectralis SD-OCT instruments during a single visit. Two Cirrus scan patterns were used: the 512 × 128 and 200 × 200 covering a 6 × 6 mm (20° × 20°) area. The Spectralis scan pattern consisted of seven B-scans, averaged 51 times, covering a 30° × 5° area. The main outcome measures were the retinal thickness at the foveal center and the number of segmentation failures on the central B-scan.

Results: The Spectralis algorithm failed to follow the proper retinal contour in 25 eyes (92.6%), while the segmentation on the Cirrus instrument was successful in every central B-scan. Spectralis yielded greater retinal thickness measurements in all cases, and the average difference between Cirrus and Spectralis was 139 μm (P < .001). The intraclass correlation coefficient between the two Cirrus scan patterns was 0.998, and Cirrus versus Spectralis was 0.21.

Conclusions: The Cirrus SD-OCT instrument identifies the appropriate segmentation boundaries in the presence PED. The Spectralis SD-OCT algorithm was unreliable in segmenting PEDs, leading to inaccurate retinal thickness measurements unless manual adjustments were performed.