Fu Dan, Li Meiyan, Zeng Li, Shang Jianmin, Yu Zhiqiang, Zhou Xingtao
Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, Fudan University, Shanghai, China.
NHC Key Laboratory of Myopia (Fudan University), Key Laboratory of Myopia, Chinese Academy of Medical Science, Shanghai, China.
Ann Transl Med. 2021 Mar;9(5):380. doi: 10.21037/atm-20-5698.
Investigating the impact of magnification correction in macular vessel density using optical coherence tomography angiography (OCTA) in patients with anisometropia.
Cross-sectional study. Totally 47 patients (11 male, 36 female) aged >18 years with high myopia were analyzed. All patients underwent evaluation of visual acuity, subjective refraction, and axial length. Anisometropia (n=37) was defined as a refraction difference between paired eyes ≥0.75 D. The control group (n=10) consisted patients with a refraction difference ≤0.5 D. Superficial vessel density was performed using 3 mm × 3 mm Cirrus-HD OCTA protocol. The vessel length density (VLD) and foveal avascular zone area (FAZA) were analyzed before and after magnification correction using Bennett's formula.
The mean spherical equivalent (SE) was -10.54±3.47 D in the more myopic eye and -8.05±3.47 D in the contralateral eye (P<0.001). Before magnification correction, the mean perfusion density (PD) and VLD were both significantly lower in the more myopic eyes. After magnification correction, the VLD and PD did not differ between paired eyes. No statistical difference was found in terms of the FAZA between paired eyes regardless of magnification correction. The magnification-induced differences in both VLD and PD were positively correlated with the difference in SE (both r=0.86, P<0.001).
In OCTA analysis, magnification correction should be performed to reduce refraction error-induced image error, which deserves attention in the clinical application.
研究在屈光参差患者中使用光学相干断层扫描血管造影（OCTA）进行放大率校正对黄斑血管密度的影响。
横断面研究。分析了47例年龄>18岁的高度近视患者（11例男性，36例女性）。所有患者均接受了视力、主观验光和眼轴长度评估。屈光参差（n = 37）定义为双眼屈光差值≥0.75 D。对照组（n = 10）由屈光差值≤0.5 D的患者组成。使用3 mm×3 mm的Cirrus-HD OCTA方案测量表层血管密度。使用贝内特公式在放大率校正前后分析血管长度密度（VLD）和黄斑无血管区面积（FAZA）。
更高度近视眼的平均球镜当量（SE）为-10.54±3.47 D，对侧眼为-8.05±3.47 D（P<0.001）。在放大率校正前，更高度近视眼的平均灌注密度（PD）和VLD均显著较低。放大率校正后，双眼的VLD和PD无差异。无论放大率校正与否，双眼之间的FAZA均无统计学差异。VLD和PD的放大率诱导差异均与SE差异呈正相关（r均=0.86，P<0.001）。
在OCTA分析中，应进行放大率校正以减少屈光误差引起的图像误差，这在临床应用中值得关注。
