Contact lenses will not melt unless you put them on fire. They will not, however, melt in your eyes as a result of typical heat or weather circumstances. Contact lenses are comprised of hydrogel, and their melting point is nowhere near that of your body. If you were to wear contact lenses and they started to melt, this would be an indication that you should never wear such lenses again. Contacts can cause problems for people who have eye injuries, eye diseases, or wear prescription glasses or contact lenses. Your optometrist will explain these options to you. It is important to understand that although contacts do not normally melt, they can cause damage to your eyes if they come off too quickly. This can happen if you remove them during an impact with enough force to break the string that holds them in place - like when you hit something hard enough to hurt yourself. If this happens, immediately remove the lens bit by bit until only the box remains attached to your eye. Then call your doctor so he/she can tell you what happened and give you proper instructions for removing the rest of the lens. People often ask whether it is safe to sleep with contacts in. The short answer is yes, as long as you follow some simple precautions. It is best to take out your contacts before going to bed. This will allow your eyes time to relax while still keeping the contact lenses in place.