Peter Russo, director of the Contact Lens Program at Loyola University Medical Center near Chicago, said non-prescription Halloween contacts that come in such colors as white zombie, red vampire and "sexy sapphire" are sold illegally in beauty shops, costume stores and over the Internet.
"Contact lenses should never be worn without a prescription from a licensed optometrist or ophthalmologist," Russo said in the statement. "In fact, it is against the law to sell decorative contact lenses without a prescription."
Many buyers are teenagers and young adults and when purchased without a prescription, these lenses might not be fitted properly, and buyers usually do not receive proper instruction on how to care for and wear contacts, Russo said.
For example, users might 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.