Wearing a pair of colored contact lenses may be just what you need to put your Halloween costume over the top, but doing so could cost you your vision.

Costume contact lenses (also called “fashion” or “decorative” contact lenses) aren’t used to correct vision, but simply change the appearance of the eye. But any contact lenses sold without a prescription are dangerous and any vendor selling “over-the-counter” contact lenses without a prescription is breaking the law.

Decorative contact lenses are not “one size fits all” and wearing improperly fitting contacts can cause serious eye damage including:

• scratches on the cornea of the eye
• corneal infection
• conjunctivitis (pink eye)
• vision problems
• blindness

The problem isn’t necessarily with wearing colored or decorative contacts, but in how these contacts are obtained and cared for. Wearing any contact lenses — cosmetic or prescription — requires a prescription and proper fitting from a licensed eye doctor. Never purchase contact lenses from street vendors, salons or beauty supply stores, boutiques, novelty stores, flea markets or Halloween stores or from an online seller without a prescription.

To safely wear decorative contact lenses, the FDA offers these tips:

• Schedule an eye exam with a licensed eye doctor (ophthalmologist or optometrist), even if you don’t need vision correction.
• Get a valid prescription that includes brand name, lens measurements and an expiration date.
• Do not wear anime or circle lenses that are larger than the standard contact lens, giving the wearer a wide-eyed look.
• Only purchase lenses from a seller that requires you to provide a prescription.
• Follow all directions for cleaning, disinfecting and wearing contact lenses and see your eye doctor for follow-up eye exams.

See your eye doctor immediately if you notice any signs of eye problems, including: redness, eye pain or decreased vision.