From the Imaging, Biomechanics and Mathematical Modelling Solutions Lab, Narayana Nethralaya Foundation, Bangalore, India (Patil, Patel, Pisharody, Narasimhan, Sinha Roy); University Eye Clinic Maastricht, Maastricht University Medical Center, Maastricht, the Netherlands (Patil, Nuijts); Department of Cornea and Refractive Surgery, Narayana Nethralaya, Bangalore, India (Shetty); Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria (Pircher, Hitzenberger).
J Cataract Refract Surg. 2023 Jan 1;49(1):76-83. doi: 10.1097/j.jcrs.0000000000001033.
To assess phase retardation and corneal sublayer thickness repeatability using ultrahigh-resolution polarization-sensitive optical coherence tomography (PS-OCT).
Narayana Nethralaya Eye Hospital, Bangalore.
Observational.
In this study, all eyes were imaged using a custom-built ultrahigh-resolution PS-OCT and high-resolution hybrid OCT (MS-39). The repeatability of phase retardation en face maps and corneal sublayer thickness profiles was evaluated. The reflectivity and phase retardation were calculated from the 2 orthogonal polarization channels to generate en face maps of phase retardation and corneal sublayer thicknesses. 3 consecutive measurements of all participants were acquired for each eye. For each measurement, the participant was asked to sit back and was realigned again. The repeatability was assessed using the intraclass correlation coefficient (ICC).
The study included 20 healthy eyes of 20 participants. The phase retardation en face maps showed preferential arrangement of collagen fibrils with least retardation in the apex and maximum retardation in the periphery. The phase retardation showed excellent repeatability (ICC >0.95) in all zones. The Bowman layer and stromal layer thicknesses were measured with excellent repeatability (ICC >0.93 and >0.99, respectively). Significant differences ( P < .05) in stromal layer thickness were observed between MS-39 and PS-OCT. The repeatability of epithelial thickness measurements was better with PS-OCT than MS-39.
The combinational assessment of corneal birefringence and sublayer thicknesses shows the advanced potential of ultrahigh-resolution PS-OCT in routine clinical practice over current OCT devices.
使用超高分辨率偏振敏感光相干断层扫描（PS-OCT）评估相位延迟和角膜亚层厚度的重复性。
班加罗尔的 Narayana Nethralaya 眼科医院。
观察性研究。
本研究使用定制的超高分辨率 PS-OCT 和高分辨率混合 OCT（MS-39）对所有眼睛进行成像。评估了相位延迟明视场图和角膜亚层厚度曲线的重复性。从 2 个正交偏振通道计算反射率和相位延迟，以生成相位延迟和角膜亚层厚度的明视场图。对所有参与者的每只眼睛进行 3 次连续测量。对于每次测量，要求参与者坐回并重新对准。使用组内相关系数（ICC）评估重复性。
本研究纳入了 20 名参与者的 20 只健康眼。相位延迟明视场图显示胶原纤维的优先排列，顶点处的延迟最小，周边处的延迟最大。所有区域的相位延迟均具有极好的重复性（ICC>0.95）。Bowman 层和基质层厚度的测量具有极好的重复性（ICC>0.93 和>0.99）。MS-39 和 PS-OCT 之间观察到基质层厚度有显著差异（P<0.05）。PS-OCT 测量上皮厚度的重复性优于 MS-39。
角膜双折射和亚层厚度的综合评估表明，超高分辨率 PS-OCT 在常规临床实践中的潜力优于当前的 OCT 设备。
