NAION is the latest side effect linked to Viagra and other ED drugs. It is a condition which results from a painless swelling of the optic nerve that causes rapid reduction in vision. Those who suffer from NAION wake up with vision loss and it may worsen in one or two weeks. The main risk factors include hypertension, diabetes or fever and a different appearance of the optic nerve which an ophthalmologist can recognize.

FDA received nearly 50 NAION reports from people who were using Viagra drug. In order to play it safe, FDA demanded a new label which linked the ED drugs effect to NAION. Though all the ED drug companies followed FDA