Are eyelash extensions safe?

A popular beauty trend has eyelash salons popping up in many areas, but some experts caution that eyelash extensions come with some potentially serious health risks.

Eyelash extensions are applied by technicians who glue synthetic fibers one by one to natural lashes. The look has been gaining popularity in recent years.

"Your eyes are the window to your soul, so to be able to enhance that is something I look forward to," one woman who has been getting eyelash extensions for over a year told CBS News' Hena Daniels.

But consumers may be unknowingly putting themselves at risk for health problems. Some adhesives, for example, contain formaldehyde, which can cause allergic reactions.

"The glue products have gotten to the surface or the top layer of the eye, called the cornea, and caused problems with scarring, irritation and more long lasting damage," said Dr. Amy Zhang, and ophthalmologist at University Hospitals Case Medical Center in Cleveland.

Bacteria can also grow in fake lashes, leading to infections. What's more, some customers can lose their real lashes from repetitive treatments.

"When you apply a lot of traction to the hair follicle, it actually causes the hair follicle not to grow," Zhang said.

Experts recommend going to salons that are clean and use formaldehyde-free glue. Taking care of the lashes is also important.

"What's very crucial is they need to clean their extensions, their eye area," said Paul Byun, owner of Lash Forever in New York City. "A lot of clients, they don't touch their extensions because they want them to last long."