Federal health officials are warning people not to use decorative contact lenses as part of Halloween costumes.

Decorative lenses (search) sold without a prescription are illegal and can cause serious eye injury and even blindness, the Food and Drug Administration (search) said Thursday.

The lenses, which come in various colors and designs, have been sold without prescription in beauty salons, flea markets, convenience stores and beach shops and online, the agency said.

The lenses can lead to corneal ulcers, eye infection or swelling, allergic reactions and vision problems, the FDA said, citing injury reports it has received.

The agency said it has examined and detained numerous shipments of the lenses entering U.S. ports and has issued warning letters to U.S. businesses that may be distributing them.

"FDA will aggressively use the full range of its statutory authorities to prevent the improper distribution of these potentially dangerous products," said the agency's acting commissioner, Lester Crawford (search).

Consumers are urged to contact the FDA at 1-800-FDA-1088 to report any problems or complaints.