If costume contact lenses are part of your Halloween look this year, the Federal Trade Commission has a warning for you -- even if they're just a temporary accessory, all contact lenses require a prescription. 

Anyone who sells contact lenses without getting a copy of or verifying your prescription is breaking the law. Without a prescription, providers can sell you ill-fitting lenses. 

Contacts that don't fit can cause conjunctivitis (pink eye), scratches and sores on the cornea, or even blindness. 

The FTC says you should only buy costume lenses from retailers who ask for your prescription.

That said, if you bought some elsewhere, think twice before putting them in your eyes tonight. The FTC is also requesting that you report any retailers selling contacts illegally. 

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