Measuring Choriocapillaris Flow with OCT-A Correlates with DR Severity

Although diabetic choroidopathy is a known entity, in vivo correlation between it and diabetic retinopathy is not yet well established because of imaging-related challenges. The choriocapillaris endothelium is an important source of vascular endothelial growth factor and may have a role in the pathogenesis of neovascularization and macular edema. The ability to measure choriocapillaris disease in diabetic retinopathy (DR) may improve our understanding, not only of the disease process but also of the response to treatment.Researchers from the Casey Eye Institute in Portland, OR, quantified choriocapillaris flow deficits using projection-resolved optical coherence tomographic angiography (OCT-A) to evaluate whether they are correlated with DR. Their segmentation approach provided deficit ratio (percent area) measurements correlating with volunteer age and DR severity. This approach was capable of diagnosing DR and identifying preclinical changes in the area because of diabetes. Choriocapillaris deficit ratio can distinguish healthy eyes from diabetic eyes and DR eyes from eyes without DR. This suggests that deficits in this area could be a useful biomarker for the early detection of vasculopathy secondary to diabetes. These images from the study show how the CC deficit ratio was derived from cross-sectional and en face OCT images. The retinal fluid area was manually annotated on the en face inner retina OCT (second image) and verified on the cross-sectional OCT (first image). The CC deficit ratio was then measured after excluding both the area beneath the retinal fluid (blue) and shadows (yellow) (third image). The red dotted line on the en face OCT image denotes the location of the cross-sectional OCT.  Photo: Wang J, et al. Invest Ophthalmol Vis Sci. 2025;66(12):13.  In this retrospective study, which was published in Investigative Ophthalmology & Visual Science, OCT-A scans of 183 participants covering a range of DR severities were acquired. Shadowing artifacts caused by hard exudates, large inner retinal vessels and vitreous floaters were detected, along with the retinal fluid area. The CC deficit ratio (percentage of deficit area) was measured and compared with shadowing artifacts and the area beneath retinal fluid excluded to assess the effect of these confounding features.The researchers found a significant positive correlation between age and choriocapillaris deficit ratio in normal controls. There was no significant difference in deficit ratio between measurements excluding only shadows and those excluding both shadows and the area beneath the fluid. The choriocapillaris deficit ratio was positively correlated with DR severity. It was significantly higher in nonproliferative DR and proliferative DR patients compared to normal controls but not in those with diabetes without DR. The proposed choriocapillaris deficit segmentation method achieved high repeatability with an intraclass correlation coefficient of 0.92.“Flow deficit quantifications are an attractive candidate for inclusion in DR feature-based analysis alongside retinal pathologies (nonperfusion area, retinal neovascularization, etc.),” the researchers wrote in their paper.The team also noted that examining choriocapillaris deficits before and after anti-VEGF treatment could offer valuable insights into its effects on the area’s perfusion. Future work could specifically look at the relationship between choriocapillaris flow deficit and DME. Click here for the journal source. Wang J, Hormel T, Park DW, et al. Quantifying choriocapillaris flow deficits in diabetic retinopathy using projection-resolved OCT angiography. Invest Ophthalmol Vis Sci. 2025;66(12):13.  This article was developed by the editorial staff in conjunction with experts in the field. In the process, AI may have been among the editorial tools used to meet the goals of human editors, who approved all content.