A woman, blind for 9 years, can see again after doctors performed a rare surgery where her own tooth was inserted into eye. How does this procedure work?

The woman suffered from damaged corneas, and she seemed to have no options if she wanted to regain her sight. Luckily, one of her doctors had heard of a surgery developed in the 1960s in Italy, and in widespread use in Japan. The patient's tooth becomes the scaffold for an artificial cornea.

According to the Miami Herald:

A tooth is used, [lead surgeon Victor] Perez said, because it provides a stable, living platform of tooth, bone and cartilage that can remain alive, get nutrition from the eye and grow into a single piece with the cornea . . . The multistage procedure began in March when Dr. Yoh Sawatari, a dental surgeon at the University of Miami Medical School, extracted the tooth — coincidentally, it was Thornton's eyetooth, also called the canine tooth — shaved it flat horizontally, drilled a hole in it and inserted an acrylic lens. He implanted the tooth/lens prosthesis under the skin inside her cheek, intending to leave it there for three months so the combination could heal together. Unfortunately, she developed a sinus infection, so he had to remove it and re-implant it under a pouch of skin in her upper chest.

Meanwhile, an eye surgeon removed scar tissue lining her damaged cornea.

A month later, surgeons removed a patch of skin from the inside of her cheek and laid it over her cornea to replace the moist tissue lost to the disease.

Two months after that, Perez extracted the tooth-lens combination from her chest, cut a flap out of the skin over the center of her cornea, cut a hole down into the eye and inserted the tooth-lens. He sewed the flap shut to hold in the tooth-lens and cut a tiny hole so the lens can protrude a couple of millimeters out of the eye.

via Miami-Herald