Dai Yining, Xin Chen, Zhang Qinqin, Chu Zhongdi, Zhou Hao, Zhou Xiao, Qiao Liya, Wang Ruikang K
Department of Bioengineering, University of Washington, Seattle, WA, USA.
Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.
Quant Imaging Med Surg. 2021 Mar;11(3):948-956. doi: 10.21037/qims-20-1011.
To evaluate the impact of ocular magnification on retinal and choriocapillaris (CC) blood flow quantification in myopic eyes using swept-source optical coherence tomography angiography (SS-OCTA).
Subjects with myopia were recruited for comprehensive ophthalmic examination and SS-OCTA imaging with 6×6 mm scanning protocol. Retinal vessel area density (RVAD), retinal vessel skeleton density (RVSD), and percentage of CC flow deficits (CC FD%) were quantified within a 5-mm-diameter circle centered on the fovea before and after magnification correction using the Littman and the modified Bennett formulae.
Images from 28 myopic eyes were qualified for quantitative analyses including 12 eyes with non-high myopia (43%) and 16 eyes with high myopia (57%). The mean spherical equivalent (SE) refractive error was -8.18±4.58 diopters (D) and the mean axial length was 27.9±2.5 mm. The mean corrected RVAD was significantly lower than the uncorrected RVAD in all myopic eyes (0.51±0.02 . 0.52±0.02, P<0.001). The mean corrected RVSD was also significantly lower than the uncorrected RVSD in myopic eyes (0.13±0.01 . 0.15±0.00, P<0.001). In highly myopic eyes, the mean corrected CC FD% was significantly higher than the uncorrected CC FD% (14.9%±4.9% . 14.2%±4.5%, P=0.009). In non-highly myopic eyes, no statistically significant difference was observed between the corrected and uncorrected CC FD% measurements (11.7%±5.8% . 11.5%±5.8%, P=0.133).
Ocular magnification significantly affects the results of retinal and CC blood flow quantification with OCTA in myopic eyes. For accurate determination of the OCTA derived parameters in myopia, magnification correction should be taken into consideration.
使用扫频光学相干断层扫描血管造影（SS-OCTA）评估眼放大率对近视眼视网膜和脉络膜毛细血管（CC）血流定量的影响。
招募近视患者进行全面眼科检查，并采用6×6 mm扫描方案进行SS-OCTA成像。使用Littman公式和改良的Bennett公式，在放大率校正前后，对以黄斑中心凹为中心的直径5 mm的圆内的视网膜血管面积密度（RVAD）、视网膜血管骨架密度（RVSD）和CC血流缺损百分比（CC FD%）进行定量分析。
28只近视眼的图像符合定量分析要求，其中12只非高度近视眼（43%），16只高度近视眼（57%）。平均等效球镜（SE）屈光不正为-8.18±4.58屈光度（D），平均眼轴长度为27.9±2.5 mm。所有近视眼经校正后的平均RVAD均显著低于未校正的RVAD（0.51±0.02对0.52±0.02，P<0.001）。近视眼经校正后的平均RVSD也显著低于未校正的RVSD（0.13±0.01对0.15±0.00，P<0.001）。在高度近视眼中，经校正后的平均CC FD%显著高于未校正的CC FD%（14.9%±4.9%对14.2%±4.5%，P=0.009）。在非高度近视眼中，校正和未校正的CC FD%测量值之间未观察到统计学显著差异（11.7%±5.8%对11.5%±5.8%，P=0.133）。
眼放大率显著影响近视眼OCTA对视网膜和CC血流定量的结果。为准确测定近视眼中OCTA得出的参数，应考虑放大率校正。
