Although colored contact lenses can change the way the world sees you, if they don’t fit properly, they can permanently damage the way you see the world.

The Food and Drug Administration is warning consumers about the possible risks of using decorative contact lenses, including permanent eye damage, that have been associated with buying over-the-counter contacts, said Kimberly Rawlings, FDA spokeswoman.

“There’s the potential for these lenses to cause permanent eye injury, potentially leading to blindness,” Rawlings said.

Possible complications include scratching or swelling of the cornea, allergic reactions and a reduction in sight, Rawlings said.

“Contact lenses need to be fit by a specialist so they don’t cause more damage than they should,” said Nicolas Hamouche, an ophthalmologist at the McFarland Clinic, 1128 Duff Ave., and collaborative associate professor of biomedical sciences.

Hamouche said both prescription and non-prescription contacts can have negative side effects — including corneal infections — even if the lens does fit correctly.

To prevent such problems, contact lenses should always be properly handled and hygiene should be a priority, Hamouche said. Contact wearers should not sleep with contacts in their eyes and should check with a doctor whenever there’s a problem. They should also cut down on the number of hours they wear contacts.

“If people have the idea that they are non-prescription, they think they can use them without proper fitting and proper maintenance, and that can lead to problems,” Hamouche said.

“Handling them would be the same, but it’s how the lens fits over your cornea that should be checked.”

Angie Schroeder, junior in advertising, said she got her prescription contacts at the McFarland Clinic and has had no problems with them.

The contacts were slightly more expensive, she said, but she also got free colors as well.

“I have blue ones and green ones and purple ones,” Schroeder said. “To me, it’s another part of your outfit, like accessories or shoes.”

Emily Thorson, junior in communication studies, has bought only one color of prescription contacts since she was a senior in high school — bright green. She wears a green contact in her right eye and a clear contact in her left eye, which is blue.

“I get a lot of comments on it — people think they’re my real color,” she said.

At the West Ames Hy-Vee Vision Center, 3800 Lincoln Way, everyone who buys contacts has to be fitted for them, said Kara Tilley, manager of the Hy-Vee Vision Center.

“Here, we only will let people try on contacts if they have had a contact fitting,” she said.

“We always have to do a fitting.”

Eye Works, 3324 Orion Drive, also sells colored contacts with eye exams and fittings.

Even non-prescription contacts have to be fitted.

“A student still has to have a complete and thorough eye exam and fitting before they leave the office,” said Ric Galvin, owner of Eye Works.

“We fit you with a contact lens first, and then we have colors that you can try on in all different types of brands.”

Galvin said the store offers a wide variety of colors and designs people can choose from for a discounted price.

There are also 30-day contacts and seven-day contacts, which he said should not be harmful unless they are worn longer than recommended.

“Especially disposable contacts, they’re more apt to tear than a regular contact, but as long as people are handling them properly and wearing them for the correct amount of time, then it shouldn’t be a problem,” Tilley said.