Department of Ophthalmology and Visual Sciences, College of Medicine, University of Iowa, Iowa City, Iowa 52242, USA. sohan-hayreh@uiowa.edu
The recent reports of non-arteritic anterior ischemic optic neuropathy (NAION) occurring shortly after ingestion of erectile dysfunction agents have raised the question of whether these agents have a cause-and-effect relationship to NAION. The nature of optic nerve head blood flow and the various factors that influence it, the systemic vascular effects of these agents, and the clinical features of NAION lead me to believe that these agents are contributory factors. Patients with the appropriate risk factors should, therefore, be warned of this possibility and advised to refrain from using these agents.