A lawsuit was filed against Pfizer Inc. on behalf a Texas man who claims he suffered blindness after taking its erectile dysfunction drug Viagra, Reuters reported last week.

In May, the Food and Drug Administration said it was examining rare reports of partial vision loss in some men taking impotence drugs Viagra and rival drug Cialis (made by Eli Lilly & Co.).

Pfizer said over the past seven years reports of Viagra causing visual field loss due to non-arteritic anterior ischemic optic neuropathy (NAION) are extremely rare.

The Lawsuit was filed in the U.S. District Court for the Southern District of Texas and is seeking class action status.

More than 23 million men have used Viagra worldwide.

(via Reuters)