Department of Ophthalmology and Visual Sciences, Dalhousie University and Nova Scotia Health, Halifax, Nova Scotia, Canada.
Heidelberg Engineering GmbH, Heidelberg, Germany.
Invest Ophthalmol Vis Sci. 2024 Oct 1;65(12):10. doi: 10.1167/iovs.65.12.10.
To assess the impact of working distance (WD) on optical distortion in optical coherence tomography (OCT) imaging and to evaluate the effectiveness of optical distortion correction in achieving consistent retinal Bruch's membrane (BM) layer curvature, regardless of variations in WD.
Ten subjects underwent OCT imaging with four serial macular volume scans, each employing distinct WD settings adjusted by balancing the sample and reference arm of the OCT interferometer (eye length settings changed). Either of two types of 30° standard objectives (SOs) was used. A ray tracing model was used to correct optical distortion, and BM layer curvature (represented as the second derivative of the curve) was measured. Linear mixed effects (LME) modeling was used to analyze factors associated with BM layer curvature, both before and after distortion correction.
WD exhibited significant associations with axial length (β = -1.35, P < 0.001), SO type (P < 0.001), and eye length settings (P < 0.001). After optical distortion correction, the mean ± SD BM layer curvature significantly increased from 16.80 ± 10.08 µm-1 to 49.31 ± 7.50 µm-1 (P < 0.001). The LME model showed a significant positive association between BM layer curvature and WD (β = 1.94, P < 0.001). After distortion correction, the percentage change in BM layer curvature due to a 1-mm WD alteration decreased from 9.75% to 0.25%.
Correcting optical distortion in OCT imaging significantly mitigates the influence of WD on BM layer curvature, enabling a more accurate analysis of posterior eye morphology, especially when variations in WD are unavoidable.
评估工作距离（WD）对光相干断层扫描（OCT）成像中光学失真的影响，并评估光学失真校正在实现一致的视网膜布鲁赫膜（BM）层曲率方面的有效性，无论 WD 的变化如何。
十名受试者接受了 OCT 成像，共进行了四次连续的黄斑体积扫描，每次扫描都使用不同的 WD 设置，通过平衡 OCT 干涉仪的样本臂和参考臂（改变眼长设置）来调整。使用两种 30°标准物镜（SO）中的任意一种。使用光线追踪模型校正光学失真，并测量 BM 层曲率（表示为曲线的二阶导数）。线性混合效应（LME）模型用于分析在进行失真校正前后与 BM 层曲率相关的因素。
WD 与眼轴长度（β=-1.35，P<0.001）、SO 类型（P<0.001）和眼长设置（P<0.001）显著相关。在进行光学失真校正后，BM 层曲率的平均值±标准差从 16.80±10.08μm-1显著增加到 49.31±7.50μm-1（P<0.001）。LME 模型显示 BM 层曲率与 WD 之间存在显著的正相关关系（β=1.94，P<0.001）。在进行失真校正后，由于 WD 改变 1mm 引起的 BM 层曲率变化百分比从 9.75%降低至 0.25%。
在 OCT 成像中校正光学失真显著减轻了 WD 对 BM 层曲率的影响，使对后眼部形态的更准确分析成为可能，尤其是在不可避免地存在 WD 变化时。
