Analysis of the choroidal vascularity in asymmetric pseudoexfoliative glaucoma using optical coherence tomography-based image binarization

PURPOSE: To analyse choroidal vascular properties using an image binarization tool in patients with asymmetric pseudoexfoliative glaucoma (PXG) and compare them with healthy individuals. METHODS: This cross-sectional study included 144 eyes of 96 patients. The eyes were divided into three groups: 48 glaucomatous eyes and 48 non-glaucomatous contralateral eyes with no clinically observable pseudoexfoliation material of patients with asymmetric PXG, and 48 control eyes. Enhanced depth imaging optical coherence tomography scans of the macula and 3.4-mm diameter, 360-degree circle scans of the optic nerve head were binarized using ImageJ software (National Institutes of Health, Bethesda, MD, USA). The choroidal vascularity index (CVI) was calculated as the ratio of the luminal area to the total circumscribed choroidal area. RESULTS: The macular CVI (mCVI) was significantly lower in the glaucomatous eyes than in the fellow eyes (p=0.007) and the control eyes (p=0.001). The peripapillary CVI (pCVI) in all sectors was significantly lower in the glaucomatous eyes than in the other two groups (all p<0.05). Non-glaucomatous fellow eyes had lower CVI values in the macula and in the peripapillary region, except for the superior-nasal and nasal sectors, compared to the control eyes (all p<0.05). In multivariate regression analysis, while the cup-to-disc ratio was negatively associated with the pCVI, AL was negatively associated with the mCVI in both eyes of patients with PXG. CONCLUSIONS: CVI was decreased in the macula and peripapillary area in glaucomatous eyes. Furthermore, the CVI tended to decrease in non-glaucomatous fellow eyes of PXG patients. This finding may suggest subclinical involvement and require further exploration into the pathogenesis of glaucoma.