If you're considering decorative contact lenses to round out a Halloween costume, consider getting them from an ophthalmologist rather than a costume store.
Ill fitting lenses can easily scratch the cornea, explains GBMC pediatric ophthalmologist Dr. Allison Jensen. This can lead to infections resulting in blindness or even eye loss. The storage solution for decorative lenses is not FDA regulated and could contain chemicals that could harm the eye.
Dr. Jensen suggests being fitted get getting a prescription from a licensed ophthalmologist. Many trusted contact lens brands carry FDA approved decorative lenses.