From the School of Optometry & Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Queensland, Australia.
From the School of Optometry & Vision Science, Queensland University of Technology, Kelvin Grove, Brisbane, Queensland, Australia.
Am J Ophthalmol. 2021 Sep;229:230-241. doi: 10.1016/j.ajo.2021.04.012. Epub 2021 Apr 24.
To assess the effect of changing anterior eye refractive power with contact lenses on the transverse magnification of en face images and associated vascular indices from optical coherence tomographic angiography (OCT-A).
Prospective crossover study.
Spherical soft contact lenses (-6 diopter [D] to +6 D in 2 D steps) were used to induce anterior eye refractive power changes in 11 healthy young adults and 3 × 3-mm macular scans were captured using OCT-A (Zeiss AngioPlex, software version 11.0; Cirrus HD-OCT 5000, Carl Zeiss Meditec Inc). Image transverse magnification was predicted based on refraction and biometry measurements and compared with empirical changes in the en face images measured with image analysis. Linear regression analysis was performed to assess the relationship between induced refractive ametropia and foveal avascular zone (FAZ) area, perimeter, circularity, and vessel density and perfusion density.
The predicted transverse magnification was linearly related to induced refractive ametropia and to the empirical transverse magnification changes (average slope: 1.02, 95% CI: 0.90-1.34). All the OCT-A indices showed linear relationships with induced refractive ametropia (P < .05) with the 12 D tested range altering the indices by 7% to 12%. After correcting for transverse magnification, all OCT-A indices except FAZ area were linearly related to induced refractive ametropia (P < .05) and were reduced to 1% to 9%.
This study is the first to show that induced refractive ametropia can affect OCT-A image magnification and indices. These changes are clinically important and need to be considered along with biometry effects when interpreting OCT-A indices. Transverse magnification changes can affect the ability of OCT-A to precisely measure linear dimensions of blood vessels.
评估通过接触镜改变眼前节屈光力对光学相干断层扫描血管造影（OCT-A）中眼前节图像的横向放大率和相关血管指数的影响。
前瞻性交叉研究。
在 11 名健康年轻成年人中使用球性软镜（-6 屈光度[D]至+6 D，每 2 D 一步）诱导眼前节屈光力变化，并使用 OCT-A（蔡司 AngioPlex，软件版本 11.0；Cirrus HD-OCT 5000，卡尔蔡司医疗技术公司）捕获 3×3-mm 黄斑扫描。根据折射和生物测量测量值预测图像的横向放大率，并与使用图像分析测量的面图像中的经验性变化进行比较。进行线性回归分析，以评估诱导屈光不正与中心凹无血管区（FAZ）面积、周长、圆度和血管密度及灌注密度之间的关系。
预测的横向放大率与诱导的屈光不正和经验性的横向放大率变化呈线性相关（平均斜率：1.02，95%置信区间：0.90-1.34）。所有 OCT-A 指数均与诱导的屈光不正呈线性相关（P<0.05），在测试的 12 D 范围内，这些指数变化为 7%至 12%。在考虑横向放大率后，所有 OCT-A 指数（除 FAZ 面积外）均与诱导的屈光不正呈线性相关（P<0.05），并降低至 1%至 9%。
本研究首次表明，诱导的屈光不正会影响 OCT-A 图像的放大率和指数。这些变化具有临床意义，在解释 OCT-A 指数时，需要与生物测量效应一起考虑。横向放大率的变化会影响 OCT-A 精确测量血管线性尺寸的能力。
