Ischemic optic neuropathies are among the leading causes of severe visual acuity loss in people over 50 years of age. They constitute a set of various entities that are clinically, etiologically and therapeutically different. Anatomically, it is necessary to distinguish anterior and posterior forms. From an etiological point of view, the diagnosis of the arteritic form due to giant cell arteritis requires emergent management to prevent blindness and even death in the absence of prompt corticosteroid treatment. When this diagnosis has been ruled out with certainty, non-arteritic ischemic optic neuropathies represent a vast etiological context that in the majority of cases involves a local predisposing factor (small optic nerves, disc drusen) with a precipitating factor (severe hypotension, general anesthesia or dialysis) in a context of vascular disease (sleep apnea syndrome, hypertension, diabetes, etc.). In the absence of specific available treatment, it is the responsibility of the clinician to identify the risk factors involved, in order to reduce the risk of contralateral recurrence that may occur even several years later. Due to their complexity, these pathologies are the subject of debates regarding both the pathophysiological and therapeutic perspectives; this review aims to provide a synthesis of validated knowledge while discussing controversial data.