Viagra can cause permanent vision loss in some men, University of Minnesota Researchers say

Ophthalmologists at the University of Minnesota say that a condition that causes permanent vision loss has been diagnosed in a small group of men who have taken the erectile dysfunction drug Viagra. The condition, nonarteritic ischemic optic neuropathy (NAION), described as "stroke of the eye," occurs when blood flow is cut off to the optic nerve, which injures the nerve and results in permanent vision loss. These cases were published in the March 2005 issue of the Journal of Neuro-ophthalmology.