It depends. As we know, contact lenses are medical devices that used to provide your eyes vision aids. Of course, there are colored contact lenses that used for both looks and vision aids. If you buy novelty contact lenses, you shall buy them from optical shop that the contact lenses are specifically for you that according to your vision aids and eye ball.
As long as the novelty contact lenses are fitted to you properly and you take good care of them, they are safe to wear. Novelty contact lenses are sometimes called cosmetic contact lenses with different colours, patterns and looks available. No matter whether you need prescription in your lenses, you should go to see a doctor to have your eyes examed so that the doctor can make novelty contact lenses that are fit specifically for you. Make sure you know how to use them properly. Using them improperly can cause some eye problems. Besides, you should know how to clean and store them in a correct way.