The recent introduction of optical coherence tomography (OCT) angiography has sparked interest in evaluating vascular alterations in the retina and optic nerve head for diagnosis, staging, and monitoring in glaucoma. In this study, Jia and colleagues provided the first account of vascular abnormalities at the optic nerve head measured by a swept-source OCT in glaucoma. They showed that the optic disc flow index was reduced by 25% in glaucomatous eyes (0.161±0.008) compared with healthy eyes (0.121±0.026). Using a cut-off value of 0.1515, they showed that the sensitivity and specificity for the detection of glaucoma were both 100% (the visual field mean deviation in the glaucoma group was -3.28±4.12dB). The flow index was highly associated with visual field pattern standard deviation (R²=0.752). This Recommendation is of an article referenced in an F1000 Faculty Review also written by Kelvin H. Wan and Christopher K.S. Leung.