Lady Gaga is known for her outrageous styles, but her latest fashion trend is generating a lot of worry from optometrists.

The bug-eyed look that Gaga sports in her hugely popular "Bad Romance" video was most likely generated by a computer. But it has helped inspire a number of fans to seek out "circle lenses," coloured contact lenses designed to make the eyes seem larger by covering not just the iris, but also part of the whites of the eyes.

Lady Gaga may be bringing the trend to the mainstream, but many circle lens lovers say the singer didn't start the trend. The lenses actually became popular a few years ago, starting in Asia, where many were trying to replicate the wide-eyed child-like appearance of Japanese anime animation.

Now, Asia has become the biggest exporters of the lenses, which are widely available online. They typically sell for just $20 to $30 a pair, both in prescription strengths, and as accessories.

Dr. Desmond Fonn who established the Centre for Contact Lens Research at the School of Optometry at the University of Waterloo, says he finds it worrying that the lenses are so very cheap.

"We don't know what these lenses are made of. We assume they're regular soft contact lenses, but because of the way in which they're sold, they must be made less expensively to make them marketable," he told CTV's Canada AM Wednesday.

He notes that the size of the lenses themselves isn't a concern; in fact, the lenses aren't any bigger than regular contacts; only the coloured iris part is wider.

But he worries that young people -- women mostly -- are buying the lenses without being instructed on how to care for and clean them.

"The biggest concern is that the majority of the young kids who use these lenses buy them but have no education about them," he said.

Fonn and other optometrists say there are lots of dangers inherent to buying contact lenses from anyone other than an eye care professional. If they don't fit right, there is the possibility of corneal abrasion. If the lenses aren't properly disinfected, there is the risk of conjunctivitis, an infection of the membrane lining the eyelids. An allergic reaction is another possibility.

"The very worst thing that can occur is very serious corneal infection," says Fonn.

"And there's scientific evidence to suggest that if you buy lenses on the Internet, there's a two to three times increased risk of developing serious corneal infection – corneal infection that can't be mediated with therapeutic drugs. So it might eventually end up that patient having to have corneal transplant."

Fonn worries that patients can order prescription contacts over the Internet without actually having to present a prescription, so customers can choose the strength of their lenses as freely as they choose their colour.

But what angers Fonn most is that while prescription contact lenses are classified by Health Canada as medical devices, novelty lenses are not. So while corrective lenses must be licensed by Health Canada before they can be imported and sold in Canada, anyone can sell novelty lenses.

"Almost every other country in the world classifies contact lenses as a medical device," says Fonn. "For some reason, coloured contact lenses and fun lenses in Canada haven't been given that designation."

He says he doesn't understand why novelty lenses aren't licensed, since they are placed onto the eye and can be just as dangerous as improperly used corrective lenses.