"Are Colored Contact Lenses Safe?"

Colored contact lenses are safe to wear provided that you follow these precautions and eye doctor recommendations:

Your colored contacts are approved by the FDA (US Food and Drug Administration), Health Canada, or health regulatory body in your country.
You are professionally fitted for colored contacts by an eye care professional such as an optometrist or ophthalmologist.
You have a valid and verifiable prescription from your eye care professional. This is true EVEN if you want plano lenses without any vision correction. In the US, your prescription must be verified by online retailers before filling and shipping the lenses to you. In Canada, colored contacts are considered cosmetic so there is no verification process is required. However, a proper fitting for contacts is still essential.
You do not under any circumstances share your contact lenses with others. Even if you just want to try on a different color for fun. Colored contacts are fitted to specific parameters. By sharing or improperly handling lenses, you can transmit bacteria that cause infection or harmful eye conditions.
You follow the advice of your eye care professional on wearing, caring for, and disposing of your contact lenses, including getting prescription refills at the recommended intervals, and keeping your prescription up-to-date. In the US, prescriptions more than one year old are invalid.
You handle your colored contacts properly and safely, including washing and drying hands before touching your lenses, cleaning, rinsing and disinfecting lenses after use with the proper products, discarding daily colored disposable lenses at the end of the day, even if they still feel fine.
You insert your colored contacts BEFORE applying makeup, and remove your lenses BEFORE removing makeup.
Replace lens cases every three months to avoid bacteria contamination and keep lens cases dry when not storing lenses.
You never wet lenses with tap water or saliva, and never reuse disinfecting solution.