Choroidal Vascularity Index in Primary Open Angle Glaucoma

Objective: To study the choroidal vascularity index (CVI) and choroidal thickness changes in primary open-angle glaucoma (POAG) compared to healthy control eyes with the enhanced depth imaging (EDI) modality of an optical coherence tomography (OCT). Methods: In this cross-sectional observational study, the CVI and the subfoveal choroidal thickness were assessed with EDI OCT and compared among 31 POAG cases and 25 healthy controls, which were age- and sex-matched. EDI OCT images were binarized into luminal area (LA) and stromal area. The CVI was defined as proportion of the luminal area to the total circumscribed choroidal area. The correlation between the visual field mean deviation (MD) value and choroidal parameters of the POAG cases were also evaluated. Results: The eyes with POAG had lower mean CVI compared to the control eyes (p<0.00001) while the mean choroidal thickness values were mostly similar (p=0.94). The CVI values of the POAG eyes had significant correlation with the visual field MD values (r=0.51, p=0.01), while choroidal thickness values of the POAG eyes did not demonstrate such an association with the visual field MD values (r=0.14, p=0.51). Conclusion: The lower CVI in POAG eyes compared to healthy controls and its significant correlation with the severity of glaucoma imply the role of choroidal vascularity in POAG pathogenesis.