Creepy costume lenses might add a spine-tingling thrill to your Halloween costume, but wearing costume contact lenses without a prescription can lead to serious eye infections or permanent vision loss.

Decorative lenses are medical devices, not costume jewelry. They must be prescribed and fitted by an eye care professional, just like regular contact lenses. That’s why the American Academy of Ophthalmology is urging people to buy decorative contact lenses only from retailers who require a prescription and sell FDA-approved products.

A poorly fitted contact lens can easily scrape the cornea, the outer layer of the eye, making the eye more vulnerable to infection-causing bacteria and viruses. Sometimes scarring from an infection is so bad, a corneal transplant is required to restore vision. The most extreme cases can end in blindness.

Although it is illegal to sell non-prescription contact lenses, they are available at costume shops, gas stations, corner shops, and online. Research shows that people who purchase contacts without a prescription face a 16-fold increased risk of developing an infection.

The Academy offers the following tips to help ensure your Halloween costume won’t haunt you long after Oct. 31:

  • See an eye care professional to get a prescription for costume contact lenses. Packaging that claims “one size fits all” or “no need to see an eye doctor” is false. Get properly fitted by an ophthalmologist (physicians and surgeons who specialize in medical and surgical eye care) or optometrist (healthcare professionals who provide primary vision care).
  • Properly care for contact lenses. Even if you have a prescription for contact lenses, proper care remains essential. Watch this video to learn the eight steps to protect your eyes from contact lens infections.
  • Never share contacts. Pink eye isn’t a good look, even for a costume. Sharing contacts can spread germs, causing conditions such as pink eye, which is highly contagious.
  • Spread the word to others about the dangers of costume contacts. Don’t let friends make the mistake of wearing costume contacts without a prescription.