Viagra and Blindness - final verdict

February 8, 2008

May 2005, the TV, radio and the print media were flooded with news about blindness among 38 patients taking Viagra, 4 taking Cialis, and one taking Levitra. Prompting this was an article in an ophthalmology journal by Dr. Howard Pomeranz of the University of Minnesota. The vital question now is: Did any of these pills cause the blindness? What is Viagra?
Sildenafil Citrate (commonly known as Viagra) is pill for the management of Erectile Dysfunction (ED) in men. The drug acts to chemically induce the dilatation (opening or relaxing) of the tiny blood vessels in the penis to allow it to fill up with blood and promote congestion, thus cause a stiff and lasting erection for effective penetration. Its newer competitor pills are Cialis and Levitra.

Is ED impotence?
No. Impotence means inability to fertilize an ovum (egg from a woman’s ovary) and effect pregnancy. Sometimes, the term is also loosely used (a misnomer) for inability to have an erection, which is technically and more accurately Erectile Dysfunction. Impotence may have erectile dysfunction as a component, but the main criterion to define that term is the inability to cause pregnancy. On the other hand, men who have ED and normal sperm, no matter how young or old they are, when properly treated with medications for ED, like Viagra, Cialis, Levitra, can successfully cause pregnancy in healthy women in child bearing age.

Are there young men with ED?
Yes, ED is not a monopoly of “old” men. There are a significant number of men as young as in their 30s or 40s who have erectile dysfunction. This is usually not organic in origin (not due to a disease), but cause by factors like stress from their job, hectic schedules, marital discord, etc. This is where these pills for ED work very well, a blessing courtesy of progress in medical science.

What diseases cause ED?
Arteriosclerosis (hardening of the artery), hypertension (high blood pressure), coronary heart disease, Diabetes Mellitus, hypercholesterolemia (high blood cholesterol) are the most common cause of erectile dysfunction in men, 50 and older. Stress also aggravates ED among those with arteriosclerosis and diabetes. ED pills are also effective here, except for those where the illness is severe. Some severe psychiatric conditions can also cause ED in various age groups. The ED drug may not be as useful in these cases.

What is this news about Viagra and blindness?
Thirty-eight cases of partial blindness among men taking Viagra, four among those taking Cialis, and one among men taking Levitra, were reported by physicians to the US Food and Drug Administration in May 2005. The reported visual impairment is known as Non-arteritic Anterior Ischemic Optic Neuropathy (NAION).

Do these ED pills cause blindness?
“We’re not able to specifically say that these cases are a result of the patients’ taking Viagra, because they may have other predisposing conditions,” said Suzanne Trevino, a spokeswoman for the F.D.A. It is not proven that these pills actually cause the vision problem. In fact, NAION is common among men over fifty years old who have the diseases listed above, which are also factors that contribute to problem with erection. In China where these ED pills are widely used, there were no reports of blindness or any visual problems among the pills users.

Any there studies done on this problem?
One hundred and three independent clinical trials were done involving 13,000 persons taking Viagra found no report of NAION. Since 1998 when Viagra was approved by the US-FDA, more than 23 million men worldwide have been prescribed Viagra and “reports of visual field loss due to NAION are extremely rare; and, there is no evidence that NAION occurred more frequently in men taking Viagra than men of similar age and health who did not take Viagra,” says its manufacturer, Pfizer. The company continues to vouch for its safety profile.

How prevalent is NAION?
NAION is one of the commonest causes of sudden blindness in older people, even before these ED pills were discovered. Statistics estimate 1,000 to 6,000 cases occur each year among those with any of the various disease risk factors enumerated above which also cause erectile dysfunction.

So, what’s the final verdict?
The jury is still out there. No final conclusion has been drawn. Countless scientific clinical investigations prompted by this report are taking place in the medical community all over the world to determine if there is any causal relationship at all between these ED pills and the reported sudden loss of vision. So far, the evidence is not there.

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