Influence of Viagra (Sildenafil) on visual impairment

One of the varieties of the side effect of Viagra (sildenafil) is a violation of vision - for some reason itimmediately attracts attention.

The vision disorder that most often occurs when taking Viagra is described as follows: a person sees everything in blue and a little fuzzy, as if looking through a bright blue grid. Some patients note blurred images and increased sensitivity to bright light. Others report difficulties in distinguishing between green and blue colors.

As a result of clinical studies it has been established that visual impairment in the use of Viagra is quite moderate, lasting only a few hours and occurs in about three percent of consumers. Disorders of vision are more often manifested when using high doses of the drug.

Thus, among men who took Viagra (sildenafil) at a dosage of 100 mg, visual impairment was detected in 11% of the patients, compared with 3% among those who receives medication in smaller doses.

Why does Viagra break vision? The fact is that the main mechanism of action of this drug is the blockade of the ferment 5-phosphodiesterase. Almost all this ferment is contained mainly in the genitals - that is why the "organ-target" in Viagra is so specific - the penis. But in the human body there are other ferments similar to 5-PDE in structure although in much smaller quantities. Viagra (Sildenafil) also acts on these ferments - and one of them 6-phosphodiesterase is contained in the human eye.

Visual disorders with the use of Viagra were found already in the first weeks of receipt of this drug in the pharmacy network and attracted close attention of the press. In the news, reports began to appear that Viagra is much frequently causes visual disturbances, possibly because some men abuse the medicine, taking larger doses than the doctors prescribed.

But you can`t completely exclude the possibility that intake of Viagra can affect the vision, plus - it is possible that in the course of time other negative aspects of this drug will appear.

Specialists from the American Academy of Ophthalmology advise men taking Viagra to pay special attention to visual disorders, especially if these patients suffer from some eye diseases - for example, macular degeneration or pigmented retinitis. By the way, on the annotation to Viagra there is a note that patients suffering from pigmented retinitis should use the medication with extreme caution.

The staff of the medical faculty of Stanford University interested in the problem of visual impairment in the case of an overdose of Viagra and investigated the effect on the vision of a dose of Viagra in 200 mg that is twice more, then the maximum daily dose. Dr. Michael Marmor who led the research reports that such an overdose of Viagra significantly reduces the sensitivity of cellulose on 30-50% for a period of about 5 hours.

In response to the warning of the American Academy of Ophthalmology, Pfizer carried out additional studies and proved that "visual disturbances, which are possible with the use of Viagra in normal dosage, are expressed as a rule moderately and they pass quickly." The increased doses of Viagra with the help of volunteers.