Qualitative and Quantitative Comparison of Spectral Domain and Swept Source OCT Angiography Devices in Retinal Diseases

Abstract

Purpose : To compare retinal vascular and foveal avascular zone morphology on OCT-angiography (OCTA) images and macular OCT images in subjects with retinal or choroidal abnormalities using two different OCT-angiography devices.

Methods : The retina of 31 study eyes of 21 participants with retinal or choroidal abnormalities including age-related macular degeneration, diabetic retinopathy, branch retinal vein occlusion and central retinal occlusion underwent fovea-centered 3×3mm and 6×6mm volume scans using the Topcon DRI-OCT Triton Swept-source OCT and Optovue RTVue-XR. The device-software generated en-face OCT-A images of the superficial (SCP) and deep capillary plexuses (DCP) and OCT images. By using the automatic segmentation, vessel length density (VLD), foveal avascular zone (FAZ) area, foveal avascular zone perimeter of OCTA images in the SCP and DCP and foveal center point thickness of 6 patterns of OCT images using image J software were compared between devices.

Results : After skeletonization of vessels to remove variation related to vessel width, mean (95% CI) difference of VLD between Topcon and Optovue was 8.40% (5.7%-1.1%, P<.001) and 3.33% (0.9%-5.7%, P=.008) in the SCP and DCP of 3×3mm volume scans, respectively. The mean difference of VLD was 7.72% (5.35%-10.09%, P<.001) and 8.93% (5.97%-11.88%, P<.001) in the SCP and DCP of 6×6mm volume scans, respectively. The mean difference of FAZ area was -0.17mm² (-0.25--0.10, P<.001) and 0.31mm² (0.20-0.42, P<.001) in the SCP and DCP of 3×3mm volume scans, respectively. The mean difference of FAZ area was -0.04mm² (-0.24-0.15, P=.647) and 0.62mm² (0.39-0.85, P<.001) in the SCP and DCP of 6×6mm volume scans, respectively. The mean difference of FAZ perimeter was -0.76mm (-1.22--0.31, P=.002) and 0.94mm (0.47-1.42, P<.001) in the SCP and DCP of 3×3mm volume scans, respectively. The mean difference of FAZ perimeter was -0.14mm (-0.62-0.34, P=.540) and 1.40mm (0.95-1.84, P<.001) in the SCP and DCP of 6×6mm volume scans, respectively.

Conclusions : These findings suggest VLD on Optovue was smaller than that on Topcon in either SCP or DCP on both volume of scans. FAZ area and perimeter in SCP on Optovue appeared larger than that on Topcon, but smaller in DCP. Further studies would be needed to determine if these differences are clinically relevant and how they vary across diseases, patients, and eye characteristics.

This is a 2021 ARVO Annual Meeting abstract.