A Comparison of Vessel Density in Primary Open-Angle Glaucoma and Normal-Tension Glaucoma Patients Using OCT Angiography

Purpose: To compare global peripapillary and perifoveal vessel densities between primary open-angle glaucoma (POAG) and normal-tension glaucoma (NTG) patients with the same glaucoma severity using optical coherence tomography angiography (OCTA). Methods: Subjects with POAG or NTG were recruited consecutively at the glaucoma clinic of the University of California at San Francisco. The glaucoma severity was graded as early, moderate, or severe based on the Hodapp-Parrish-Anderson Visual Field Criteria. All subjects underwent OCTA imaging (RTVue-XR Avanti; Optovue, Fremont, CA, USA) of the optic disc and macula by a trained technician. The main outcome measures were vessel density of the radial peripapillary capillary area and the perifoveal superficial layer as obtained from the disc and macula imaging respectively, using the AngioVue software. Results: The study included 156 eyes (93 POAG, 63 NTG) from 91 patients. There was no significant difference between the perifoveal and peripapillary vessel density of subjects with NTG and POAG with similar extent of glaucomatous damage. In early glaucoma, a trend toward lower peripapillary vessel density in NTG compared with POAG was observed. No such trend was seen in moderate or severe stages. Conclusion: Global vessel density parameters did not differ significantly between NTG and POAG eyes of similar severity. The observed trend toward lower peripapillary vessel density in early NTG may indicate a possible vascular contribution in early disease, but this finding is preliminary and requires confirmation in larger, prospective studies.