Viagra linked to vision loss

TEXT: A report in this month's Journal of Neuro-ophthalmology has linked the impotence drug Viagra with a serious loss of vision.
A study by University of Minnesota Medical School has identified seven men who have lost vision through a non-arteritic anterior ischaemic optic neuropathy since taking the drug.
The condition, in which the blood supply to the optic nerve head via the short posterior ciliary arteries is restricted, results in a severe, sudden loss of vision and usually a characteristic altitudinal field defect. All suffered the condition within 36 hours of starting their drug treatment, and in on case the loss was bilateral.
A spokesperson for Pfizer, the drug manufacturer, was quick to point out that no such association was detected in any of the 103 controlled trials of Viagra but said the company was 'taking the study seriously'.