WebProNews

Answering concern about reports of a rare form of sudden blindness afflicting men who had taken erectile dysfunction medications Viagra, Cialis, and Levitra, the Food and Drug Administration issued a warning label to adorn all new packaging.

The particular form of blindness, non-arteritic anterior ischemic optic neuropathy (NAION), is caused by lack of blood flow to the optic nerve and is most common in the elderly, especially among those suffering from diabetes or high blood pressure. The condition affects an estimated 1,000 to 6,000 Americans a year.

After 38 Viagra users reported sudden vision impairment soon after taking the drug, the FDA launched an investigation. It was concluded that there was not sufficient evident to link Viagra to the condition.

"At this time, it is not possible to determine whether these oral medicines for erectile dysfunction were the cause of the loss of eyesight or whether the problem is related to other factors such as high blood pressure or diabetes, or to a combination of these problems," the FDA said in a statement.

The regulatory agency did, however, decide an updated warning level should be used.

The new label reports that vision loss has been reported rarely and advises patients to stop taking the medicine and contact a physician immediately if they experience sudden or decreased vision loss in one or both eyes.

The FDA also advises patients to report any history of severe vision loss or previous bouts with NAION to their physicians. Such patients face an increased risk of developing the condition again.

Jason L. Miller is a staff writer for WebProNews covering technology and business.