To compare the real-time visualization of vitreoretino-choroidal structures using full-depth imaging (FDI) spectral domain optical coherence tomography (SD-OCT) and swept-source (SS)-OCT.Methods:
Foveal scans using both FDI SD-OCT (Heidelberg Spectralis) and SS-OCT (Topcon Deep Range Imaging-OCT-1) were obtained in 40 normal eyes, 40 eyes with macular pathologies, and 40 eyes with glaucoma. Full-depth imaging SD-OCT images were obtained by manually enhancing the vitreoretinal interface first and then the choroid while averaging each OCT B-scan 100 times. Swept-source-OCT images were obtained by averaging each B-scan 96 times. After masking and randomly mixing the original OCT images, two independent physicians graded visualization of the premacular bursa, interdigitation zone line, and chorioscleral boundary, and also sharpness of choroidal structures.Results:
A real-time full-depth image of vitreoretino-choroidal structures was successfully achieved with FDI SD-OCT in 118 cases (98.3%) and with SS-OCT in 45 cases (37.5%, P < 0.001). Full-depth imaging SD-OCT imaging was superior to SS-OCT imaging in visualizing the anterior border of the premacular bursa in 109 eyes (90.8%), with average grading of 1.63 ± 0.53 for the FDI SD-OCT and 0.39 ± 0.52 for the SS-OCT (P < 0.001). Swept-source-OCT was similar to FDI SD-OCT in visualizing the chorioscleral boundary in 108 eyes (90.0%), with average grading of 1.81 ± 0.39 for the SS-OCT and 1.78 ± 0.38 for the FDI-OCT (P = 0.566). The visualization of the interdigitation zone line was identical in the 2 imaging instruments (P = 1.000). The sharpness of the choroidal structures was greater with SS-OCT than with FDI-OCT (P < 0.001).Conclusion:
Manual double-enhancing FDI technique using SD-OCT provided a good compromise between vitreous and retinochoroidal structures visualization in real time during scanning procedure. In contrast, SS-OCT imaged well details of choroidal sublayers. Appropriate OCT technology and software should be selected according to its application in clinical settings.