Comparison of retinal layer intensity profiles from different OCT devices.

BACKGROUND AND OBJECTIVE The purpose of this study is to use automated multiple retinal layer segmentation to compare retinal layer intensity profiles between different spectral-domain optical coherence tomography (SD-OCT) devices with and without normalization. PATIENTS AND METHODS A graph-based multistage segmentation approach was used to identify 11 boundaries in horizontal SD-OCT B-scans passing through the foveal center. Four acquisition protocols from two different SD-OCT devices were applied on 34 eyes from 17 healthy participants. The mean intensity of the 11 layers was compared within each device and between the two devices. In addition, the intensity of the various layers was normalized against the vitreous and retinal pigment epithelium band, and the normalized intensity profiles were also compared. RESULTS Within each OCT device, the mean intensity of the 11 retinal layers did not show significant difference (P values of paired t test ranging between 0.15 and 0.30). For the two different devices, before normalization, the mean intensity of the 11 retinal layers differed significantly (P = .02 to .03). After normalization, the mean intensity no longer differed significantly (P = .26 to .51). Linear regression demonstrated an average R(2) of 0.94 (P < .001) before normalization and 0.98 (P < .001) after normalization between the two devices. CONCLUSION The morphology of the intensity profiles was found to be similar within each SD-OCT device. Comparing intensity profiles from the two different devices, significant differences in unnormalized layer intensity were observed. Following normalization, the differences between OCT devices were no longer significant.