Peripapillary non-flow area measurement for the measurement of progressive localized glaucomatous perfusion damage

Purpose: To investigate the applicability of peripapillary non-flow area (PNFA) measurement in the radial peripapillary capillaries (RPC) layer for the measurement of progressive localized glaucomatous perfusion damage. Methods: A research soft ware version of the Angiovue /RTVue-XR OCT (Optovue, Fremont, CA, USA) was used to measure localized PNFA progression by clicking on a predefined peripapillary non-perfusion area on prospectively acquired images. Capillary vessel density (VD) in the corresponding peripapillary sector was also measured. High-quality peripapillary Angiovue OCT VD images of an open-angle glaucoma population prospectively imaged for 2 to 2.5 years (5 or 6 visits at 6-month intervals) were investigated. Eyes with both localized PNFA at baseline and statistically significant peripapillary VD progression in the hemifield of the PNFA were selected for the analysis. Results: Four eyes of four patients were eligible. In three eyes, the Octopus visual field cluster mean defect in the cluster spatially corresponding to the area of the PNFA progressed significantly (P < 0.01) at a rate of 1.5 to 3.4 dB/year. In two eyes, neither PNFA nor sector VD showed significant correlation with the follow-up time. In one eye, significant negative correlation for sector VD (r = -0.841, P = 0.036) and almost significant positive correlation for PNFA (r = 0.803, P = 0.055) was found, while in another eye significant positive correlation for PFNA (r = 0.875, P = 0.022) but no correlation for sector VD was found. Conclusion: Our results suggest that PNFA measurement in the RPC layer is a potentially useful tool for the measurement of progression of localized glaucomatous capillary perfusion damage in open-angle glaucoma eyes with localized peripapillary non-perfusion.