Craniofacial prostheses are prostheses made by individuals trained in anaplastology or maxillofacial prosthodontics who medically help rehabilitate those with facial defects caused by disease (mostly progressed forms of skin cancer, and head and neck cancer), trauma (outer ear trauma, eye trauma) or birth defects (microtia, anophthalmia). They have the ability to replace almost any part of the face, but most commonly the ear, nose or eye/eyelids. An ocular prosthesis and hair prosthesis can also be classified as craniofacial prostheses. Prostheses are held in place either by biocompatible drying adhesives, osseointegrated implants, magnets, or another mechanical means (although rare) such as glasses or straps. Prostheses are designed to be as similar as possible to the natural anatomy of each individual. Their purpose is to cover, protect, and disguise facial disfigurements or underdevelopments.