Is There Really A Threat To Eyesight?

By Author: Thomas Strickland
Total Articles: 102
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When our grandparents were growing up, there were microscopes but, by modern standards, they were primitive. There were moderately sophisticated chemical tests for different medical problems and conditions. Sadly, they were not very precise. So, when a doctor or any other scientist made announcements, the numbers were very general. We found this acceptable. No one expected science to develop into the modern wonders of today where we can measure the presence of trace elements as parts-per-million. We may even have discovered an atomic particle capable of traveling faster than the speed of light. Einstein would be turning in his grave to get a better look at this magic neutrino that might just shoot down one of his best known theories.

Because we've moved from general statements that there were traces of a chemical to a precise measurement there were 39 parts-per-million, many now believe even minute traces can be dangerous. We've lost the sense of scale. When we can detect the presence of particles at a subatomic level, we want to believe science has more answers. It's going where no one has been able to go before, therefore ...
... it must know more than those who tried to go before. Except, science doesn't work like that. The best it can do is say people have been able to replicate the same results from experiments, so this suggests a theory is correct. But the theory is only correct until a better theory comes along with experimental evidence to back it up.

When the erectile dysfunction drugs were going through their clinical trials, there were some effects noted on eyesight. This fell into two classes. First, some men experienced a slight color shift so many objects appeared tinged with blue. Second, some men experienced photosensitivity, i.e. their eyes were painful in bright light. This affected between 3 and 10% of all men going through the trials, and the effects were duly noted on the labels and accompanying patient information. Suddenly, there were stories about men going blind. As a knee-jerk reaction, the FDA required the manufacturers to change the labels to include a warning.

In a sense, this is the precautionary principle at work. As a responsible regulator, the FDA prefers not to take any chances. Except, just how many verified cases of vision loss were there to encourage the FDA into action? The answer comes in a new piece of research. A team went through all the published reports in the peer-reviewed literature. All the results were analyzed using the international probability scales. The result? Between January 2006 and February 2011, there were eight reported cases. Eight cases over five years! And even in these cases, there's no certainty the loss of vision was due to the use of an erectile dysfunction drug. There were other equally valid explanations.

So the next time you take a Levitra, there's a slight chance you might feel a little blue coming on or you prefer the dark (not inappropriate on this occasion). These are temporary conditions and disappear in about an hour. This just leaves the big mystery as to what science was applied when the FDA insisted the label on Levitra be changed to include a warning. This is just disappointing from the FDA.