Phosphodiesterase type 5 inhibitors, visual changes, and nonarteritic anterior ischemic optic neuropathy: is there a link?

Nonarteritic anterior ischemic optic neuropathy (NAION) is the most common acute optic neuropathy and one of the most common causes of sudden vision loss in the elderly. Recently, NAION has been associated with the use of phosphodiesterase type 5 inhibitors (PDE5i) in men with erectile dysfunction (ED). A causal relationship could not be established given the large number of men safely using PDE5i and the limited number of NAION cases reported in these men. ED and NAION share common risk factors; therefore, some men with ED should be expected to develop NAION. However, sudden vision loss or decreased vision in one or both eyes demands immediate cessation of PDE5i use and urgent patient assessment. No causal relationship between PDE5i and the development of NAION exists for the moment, yet physicians should be aware of a possible adverse reaction and inform patients accordingly.