Yang Zhuoyan, Wu Yidan, Gao Jiaxin, Hu Shiyuan, Wang Jianming, Jing Ruihua
Department of Ophthalmology, The Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi Province, China.
Clin Exp Ophthalmol. 2025 Jul 22. doi: 10.1111/ceo.14585.
To evaluate changes in OCTA-derived structural and vascular parameters before and after axial length (AL) magnification correction using two different formulas, and to explore their correlations with vessel density (VD).
This study included 45 high myopic eyes and 45 age- and gender-matched controls. Both 6 × 6 mm optic nerve head imaging and biological measurement were performed using OCTA. Magnification correction was performed using both the Bennett formula and the device's built-in algorithm. Parameters analysed included retinal nerve fibre layer (RNFL) thickness, superficial vascular complex (SVC) VD, deep vascular complex (DVC) VD, and choroidal VD.
In long AL eyes, uncorrected values underestimated RNFL thickness and SVC VD but overestimated DVC VD and choroidal VD; discrepancies increased with AL. The opposite pattern was observed in shorter eyes. After correction, all vascular parameters except DVC VD showed significant changes in the high myopia group, while non-high myopic eyes showed no significant differences. The two correction methods showed strong agreement across all layers. RNFL thickness correlated strongly with SVC VD, and choroidal thickness (CT) with choroidal VD, both before and after correction. Post-correction, AL was no longer associated with RNFL thickness or SVC VD, while its correlation with CT and choroidal VD persisted. Mediation analysis showed AL fully mediated the CT-choroidal VD relationship, with a stronger effect post-correction.
Magnification correction is crucial in high myopic eyes. Both formulas showed high consistency. Correction eliminated AL's confounding effects on RNFL and SVC VD, while emphasising its mediating role between CT and choroidal VD.
使用两种不同公式评估眼轴长度（AL）放大率校正前后光学相干断层扫描血管造影（OCTA）衍生的结构和血管参数变化，并探讨它们与血管密度（VD）的相关性。
本研究纳入45只高度近视眼睛和45名年龄及性别匹配的对照者。使用OCTA进行6×6 mm视盘成像和生物学测量。使用贝内特公式和设备内置算法进行放大率校正。分析的参数包括视网膜神经纤维层（RNFL）厚度、浅表血管复合体（SVC）VD、深部血管复合体（DVC）VD和脉络膜VD。
在长眼轴眼中，未校正值低估了RNFL厚度和SVC VD，但高估了DVC VD和脉络膜VD；差异随眼轴长度增加而增大。在短眼轴眼中观察到相反的模式。校正后，除DVC VD外，所有血管参数在高度近视组均有显著变化，而非高度近视眼睛无显著差异。两种校正方法在所有层面均显示出高度一致性。校正前后，RNFL厚度与SVC VD密切相关，脉络膜厚度（CT）与脉络膜VD密切相关。校正后，眼轴长度不再与RNFL厚度或SVC VD相关，但其与CT和脉络膜VD的相关性仍然存在。中介分析表明，眼轴长度完全介导了CT与脉络膜VD的关系，校正后效应更强。
放大率校正对高度近视眼睛至关重要。两种公式显示出高度一致性。校正消除了眼轴长度对RNFL和SVC VD的混杂影响，同时强调了其在CT和脉络膜VD之间的中介作用。
