In a healthy eye, the cornea acts like a windshield, allowing light to pass through to the lens and then to the retina, where it is converted into electrical signals sent to the brain. The cornea’s clarity depends on adequate lubrication and a steady renewal of cells by limbal stem cells. In conditions like Stevens-Johnson syndrome, those systems fail.
When the cornea is permanently opaque and the eye rejects a cornea transplant, surgeons sometimes turn to tooth-in-eye surgery.
A canine tooth, which is the longest tooth in the human mouth, is extracted from the jaw, along with a thin layer of bone around the tooth that provides support and blood, keeping it alive. The tooth is then shaved into a 4 millimeter-thick block and drilled to hold a plastic optical cylinder, explained Dr. Ben Kang, Chapman’s oral maxillofacial surgeon and division head of Oral & Maxillofacial Surgery at Vancouver General Hospital.
The shaved tooth, with the lens in place, is implanted into the patient’s cheek or eyelid for several months, allowing soft tissue to grow around it.
“The tooth is a really ideal structure for holding a focusing element in place,” Moloney said. “It’s hard, it’s rigid, it survives in poor environments, and the body accepts it because it’s part of its own.”
The next step is to make a hole in the front of the patient’s eye to create space for the new complex.
Once the tooth-lens complex is integrated with living tissue, it is surgically attached to the front of the eye, replacing the damaged cornea’s function. Tissue from inside the patient’s mouth is used to cover the tooth part of the device, giving the new eye a pink shade. Light can then pass through the clear lens to the retina, enabling vision again, provided that everything behind the cornea — the retina and optic nerve— remains healthy.
Moloney said there are two types of candidates for the surgery: people like Chapman, who have tried every other procedure, or those who are so severely affected by their initial disease that doctors know from the outset that other options won’t work.
The surgery, which can take over 12 hours across two stages, is rare and performed by only a handful of specialists worldwide. But for people who qualify, success can mean regaining nearly normal vision.
