Hidden Dangers of the Little Blue Pill

Blindness, a possible and rather alarming side effect of Viagra, could make this popular impotency drug a little less fashionable. According to a report in the March 2005 issue of the Journal of Neuro-Ophthalmology, a small number of men (seven total) suffered varying degrees of vision loss within 36 hours of taking Viagra.

In Viagra’s defense, all seven men had pre-existing conditions such as hypertension, diabetes, or elevated cholesterol that could contribute to vision loss. But this finding did prompt the FDA to begin investigating 50 other reports linking vision loss to the erectile dysfunction drugs Viagra, Cialis and Levitra. The FDA has ordered new labels for the drugs warning men of possible blindness.

Doctors say that by dilating blood vessels and increasing blood flow to the penis, the drugs can sometimes lower blood pressure at the optic nerve (the part of the eye that transmits images to the brain). In rare cases, the decrease in oxygen can cause an optic nerve stroke and vision loss called non-arteritic anterior ischemic optic neuropathy or NAION.

Considering that fewer than 40 cases of Viagra-induced NAION have been reported out of about 23 million people using Viagra worldwide—the chances for an optic nerve stroke is quite small. Still, experts say the number of cases may be under-reported because doctors haven’t known to look for such a connection.

Certain risk factors, such as high blood pressure or cholesterol levels, diabetes and smoking, can make men more susceptible to an optic nerve stroke. Also, men who have smaller-than-average optic nerve heads are more prone to NAION.

So if you plan on using Viagra or similar drugs, you may want to visit your eye doctor first to assess your risk for an optic nerve stroke. She’s hardly worth the risk!

—Kristin Bjornsen