Fractal analysis of retinal vasculature in normal subjects on ultra-wide field fluorescein angiography

• 作者: Akihito Uji Alan Fleming Gavin Robertson Jano van Hemert Michael Ip Michael Singer Min Sagong SriniVas R.Sadda Wen-Ying Fan
• 来源期刊: 国际眼科杂志:英文版
• 学科: 医学
• 关键词: fractal analysis RETINA ultra-wide field fluorescein angiography normal subject
• 年，卷（期）: 2020,（7）
• 页码范围: 1109-1114
• 页数: 6页
• 分类号: R770.4

摘要

AIM: To evaluate the fractal feature of the retinal vasculature of normal eyes on a stereographic projected and montaged ultra-wide field(UWF) fluorescein angiography(FA).METHODS: Prospective, observational, cross-sectional study. Totally 59 eyes of 31 normal subjects were imaged using the Optos 200 Tx. Images obtained at different gaze angles stereographically projected and montaged. The early-phase UWF FA frames were processed to segment the retinal vasculature and the results were exported as binary masks. The fractal dimension(FD) was calculated using the box-counting method.RESULTS: The global FD for the entire retina was 1.6±0.04, with no difference between males and females(1.59±0.04 vs 1.61±0.04, P=0.084) or between right and left eyes(1.6±0.04 vs 1.6±0.05, P=0.61). FD was nonuniformly distributed among four quadrants(P<0.001) and decreased as the distance from the fovea increased(P<0.001). A negative association was observed between FD and age(R=-0.37, P=0.006), and this relationship was observed in the posterior and mid-peripheral retina(P<0.05) but absent in far-periphery(P>0.05).CONCLUSION: Fractal geometry is non-uniformly distributed across the retina in normal eyes and decreases from the fovea to the far-periphery. Subjects with an older age tend to have a smaller FD, however, the FD in the farperiphery does not appear to be influenced by age.