Although the clinical picture of primary open-angle glaucoma (POAG) is well described, the exact mechanism leading to this specific type of damage is still under investigation. Among the vascular risk factors, hypotension and vasospasm seem to have an important role in the pathogenesis of this disease. This review presents the importance of hypotension and vasospasm in the pathogenesis of POAG and an inventary of the principal methods for their detection.