Illustration showing an osteo-odonto-keratoprosthesis, a rare operation enabling people suffering from blindness to be given back their sight. The operation consists of preparing the prosthesis from the patient molar which is removed with its surrounding structures (bone and gum). A plexiglass lens is inserted in the centre of a slice produced from this sample which is then placed in the patient cheek so the patient own cells will colonize it. The eye is worked on, the lens and pupil are moved to receive the transplant which is placed between the pupil and cornea. An esthetc prosthesis imitating the iris is placed over the cornea. Light travels through the eye via the plexiglass lens to the retina and optical nerve carrying information to the brain. For this operation to work, the back of the eye has to be working and the patient has to receive light.