Federal health workers are investigating reports that some men who used Viagra may be experiencing a very unpleasant side effect — blindness. The FDA is currently meeting with health experts and Pfizer (makers of Viagra) to determine the situation.Jimmy Grant started using Viagra in 1998, when he was 57. At first, he said he felt pressure in his temples and saw color changes in his vision.

“I noticed the symptoms probably within 45 minutes to an hour,” he told a CBS News report. He soon went blind in his right eye. Doctors didn’t make the connection to Viagra.

After continuing to take the drug on occasion, Grant experienced further loss of sight in his left eye in March 2000.” A friend found an article on the internet about the possible connection between Viagra and blindness. Grant is suing Pfizer, and regrets ever having tried the drug.

“What convinced me that Viagra did it was what Dr. Pomeranz had in his report.”

Grant referred to Dr. Howard Pomeranz, an eye specialist who appears to be the first doctor to have made the connection in one of his patients back in ’98. According to him, it made sense that Viagra, by altering blood flow in key parts of the body, could also affect circulation to the optic nerve.

“And so I thought, well, in both of these situations, blood flow is being altered, so maybe there is a connection between the two,” said the University of Minnesota neuro-ophthalmologist.

He published his patient’s case in an attempt to get feedback. By 2001, he had five cases to report to the FDA and Pfizer, the makers of Viagra. Since then, more reports have trickled in.

“So they certainly are aware of this possible side effect of their medication,” Pomeranz said.

According to a CBS News report, the FDA is investigating about 50 reported cases of vision loss and, while no direct link has been proven, an FDA medical supervisor has said, “We’re very concerned. This issue is front and center, it’s a priority. We know people need to know as promptly as possible.”

Pfizer told CBS that its Viagra studies “show no report of vision loss and [that] there is no more evidence of vision loss in men taking Viagra than those who don’t.” However Pfizer confirmed it will hold discussions with the FDA regarding updating the labels to reflect the rare occurrences.

The FDA is monitoring other drugs in the same class for similar adverse reactions.