Viagra may cause vision loss

According to recent research patients develop non-arteritic ischaemic optic neuropathy (NAION), an eye problem that can result in permanent vision loss, after taking Viagra (sildenafil) for erection difficulties. For years, it has been known that some men who take Viagra experience temporary colour changes in their vision and see things as blue or green. NAION is a much more serious condition because it can lead to permanent vision loss.Researchers from the University of Minnesota in Minneapolis. With the exception of one patient whose symptoms began 24 to 36 hours after using Viagra, the patients developed symptoms within 24 hours of use. In all patients, the initial symptoms were blurred vision and some degree of vision loss. In one patient, both eyes were affected, whereas in the remainder, just one was involved. All the patients had one or more heart disease risk factors. High blood pressure was invariably present and most men also had high cholesterol levels. Three patients had pre-existing eye problems that may have increased their risk of NAION.It was found that the final vision in the patients' affected eye(s) ranged from perfect vision to only light perception. Although the above cases may represent the tip of the iceberg, the researchers said that the risk of NAION with these drugs is probably still very, very small.At this point, there is not enough data to support performing an ophthalmologic exam on every patient being considered for Viagra treatment. Still, doctors prescribing the drug should be aware of the association with NAION and consider an examination for patients with several heart disease risk factors.