An up-to-date review of the concepts on nonarteritic ischemic optic neuropathy (NION) is presented with special emphasis on its most common form, nonarteritic anterior ischemic optic neuropathy (NAION). Relevant clinical data are presented, along with the description of diagnostic and therapeutic algorithms. The methods used in clinical diagnosis and validity of expectations from particular methods during the clinical course of the disease are elaborated. Controversies of medical and surgical approach in the management of this entity are discussed, with special references to the use of aspirin and optic nerve sheath fenestration.