Disc hemorrhages can occur in patients with glaucoma and other conditions. In glaucoma patients, disc hemorrhages are markers for a complex vasculopathy that is just beginning to be understood. They are also predictors of progressive glaucomatous disease independent of intraocular pressure (IOP) and other factors. This paper reviews the differential diagnosis of disc hemorrhage, as well as evidence that suggests disc hemorrhages are an important sign in glaucoma. Lastly, it presents new evidence showing primary open-angle glaucoma (POAG) patients with disc hemorrhages have an abnormality in vascular perfusion.