What are some rules for safe contact lens wear? First, contact lenses should only be used to correct the patient's vision and not as a costume or for a decoration. They need to be fitted by a professional -- an optometrist, ophthalmologist, or optician -- who is skilled and licensed in the fitting of contact lenses. The lens should be one that has been approved by the FDA for use in humans. The lenses need to be fitted properly and the patient needs to be instructed on the proper technique for insertion, wearing, sterilization, and cleansing of the lens and storage case. Finally, those rules have to be followed carefully.
Lenses should never be worn overnight. Other high-risk use of lenses would be wearing lenses for swimming or other activities in which water or contamination would be splashed into the eyes. If a child or an adult has a red eye or a painful episode related to contact lens use, the lens should be removed immediately and the patient, along with the lens, should be sent immediately to an emergency room or, on the same day, to an eye professional to be evaluated for possible infection and started on treatment.
Those are some of the rules for safe contact lens use, but I would strongly advise that no decorative or purely cosmetic, costume contact lenses ever be used or be considered safe unless they are fitted by a professional.