Too much of what could be a good thing could bring about damaging, irreversible results.

NEW YORK CITY -- An overdose of an erectile dysfunction drug likely gave a man more than just increased confidence: irreversible vision damage.

The McClatchy News Service, citing a report published this month in Retinal Cases, says the 31-year-old man went to an urgent care clinic after a couple days of troubled vision. Namely, he was seeing red.

Doctors were told the man took "much more" than the recommended 50-mg dosage of liquid sildenafil citrate, an active ingredient in Viagra, purchased online and caused him to have red-tinted vision, according to McClatchy.

"People live by the philosophy that if a little bit is good, a lot is better," said Dr. Richard Rosen, lead author and director of Mount Sinai’s New York Eye and Ear Infirmary as quoted.

"This study shows how dangerous a large dose of a commonly used medication can be."

Doctors found the drug caused "microscopic injury to the cones of the retina, the cells which are responsible for color vision," according to researchers.

Erectile dysfunction drugs warn consumers of a slate of side-effects, including impaired vision, headaches and low blood pressure, but this is a more recent case that shows higher doses can cause irreversible effects.

►Make it easy to keep up-to-date with more stories like this. Download the 10News app now.