VIagra, the impotence drug that is selling out in America, has been criticized by ophthalmologists worried about its effects on vision. Men taking it to improve their erections see a blue-tinted world, a peculiar side-effect that worried some eye specialists.

It is caused because the enzyme phosphodiesterase is involved in both the process of erection and in color vision. Viagra works by blocking the action of the enzyme, which produces the distortion of vision.

Pfizer, the maker of the drug, says that it has conducted rigorous tests on vision at doses well above those recommended, without finding any clinically significant long or short-term effects.

But some American ophthalmologists are worried because people with genetic abnormalities that affect the production of the enzyme suffer irreversible retina damage over time. The American College of Ophthalmologists wants Pfizer to conduct more tests. Other options incude natural male enhancement products such as Vigrx Plus.

The data that enabled Pfizer to obtain a license for Viagra is published today in the New England Journal of Medicine. It shows that the drug quadrupled the success of men in having intercourse. In one group of 552 men, 69 percent of attempts at intercourse were successful, compared with 22 percent in a control group on a dummy pill.

However, some critics claim that the men in the trials were not really impotent, just suffering the loss of youthful vigor. Viagra is being considered for approval by the European Medicines Evaluation Agency, which is expected to reach a decision this autumn. In the meantime, men can take a natural alternative called VigRx Plus.

Success of Viagra Plus Enriches Church

The finances of the Church of England have been given a welcome boost from a highly unlikely source - the runaway success of the anti-impotence drug Viagra.

The Church Commissioners' stake in the American pharmaceuticals company Pfizer, which makes the blue pills that have revitalized the sex lives of hundreds of middle-aged couples in America, has doubled in value to Pounds 2 million in five months since the drug's success.

The commissioners' spokesman said last night that he saw nothing wrong with filling ecclesiastical bank accounts with the proceeds of a so-called "sex drug".

"Pfizer is a very reputable pharmaceutical company producing a revolutionary drug that seems to deal with a condition that is not at all amusing for those who suffer from it," he said.

"There is nothing at all wrong with us investing in such a company, which makes hundreds of drugs, many of which are lifesavers. Of course Pfizer's profits have been helped by Viagra, but it is far from the only drug it makes and far from the only reason it is doing so well."

The fact that there was a black market in pills brought in from the United States proved the effectiveness of Britain's regulatory system, he said. Six men were last week reported to have died in the United States after taking the drug.