Decorative tinted contact lenses will be popular accessories this Halloween, but a Loyola University Medical Center optometrist is warning that improper use without a prescription could cause severe eye damage.

"Contact lenses should never be worn without a prescription from a licensed optometrist or ophthalmologist," said Peter Russo, OD, director of the Contact Lens Program at Loyola University Medical Center. "In fact, it is against the law to sell decorative contact lenses without a prescription."

Non-prescription Halloween contacts come in such colors as white zombie, red vampire and "sexy sapphire." They are sold illegally in beauty shops, costume stores and over the internet.

Many buyers are teenagers and young adults. When purchased without a prescription, these lenses may not be fitted properly, and buyers usually do not receive proper instruction on how to care for and wear contacts. Users might, for example, use the wrong solution, share with a friend, wear improperly, fail to disinfect or use tap water rather than contact lens solution, Russo said.

Improper use can cause inflammation and infections, making eyes red and painful. Even when these complications are treated, there's still a risk that scar tissue could permanently impair vision and require a corneal transplant, Russo said.

"Even when worn for a relatively short period of time, such as during a Halloween party, decorative contact lenses can damage eyes if not used properly," Russo said. "They may seem like a lot of fun, but they're not worth the risk. Never wear a contact lens, whether for vision correction or for decoration, without a prescription."