Although contact lenses are regulated by the FDA and should only be acquired through a licensed professional, many kids, teens and young adults manage to get hold of lenses that change eye color or add frightening effects to the eyes for Halloween. These lenses are actually illegal.
From the internet, at some tattoo parlors, party supply stores and flea markets, these decorative lenses, also known as cosmetic lenses, can be purchased. Because they aren't prescription lenses, designed to fit the curves of a particular eye, they can cause irritation that leads to infection. There have been cases where people have lost their sight by using these novelty lenses.
There is no small number of websites that offer these novelty lenses for a relatively inexpensive price.
Eye irritation is caused by ill-fitted lenses, improper cleaning of the contacts before using and from constantly rubbing the eyes while wearing the contacts. Even a tiny scratch will allow bacteria to enter the eye. The FDA says this about novelty contact lenses:
If You Want Decorative Contacts:
Get an eye exam from a licensed eye care professional, even if you feel your vision is perfect.
Get a valid prescription that includes the brand and lens dimensions.
Buy the lenses from an eye care professional or from a vendor who requires that you provide prescription information for the lenses.
Follow directions for cleaning, disinfecting, and wearing the lenses, and visit your eye care professional for follow-up eye exams.
Nothing is worth the risk of losing your vision. Halloween is one night of the year, but the loss of vision is permanent. Parents should explain these risks to kids. Never assume your child would ask you first before acquiring novelty lenses.