Surgeons implant teeth in patients’ eyes to restore vision

A trio of Canadians are on track to become the country’s first residents to have their eyesight restored thanks in part to their teeth. Osteo-odonto keratoprosthesis, more commonly known as “tooth-in-eye” surgery, involves harvesting the body’s strongest natural substance to craft a specialized lens implant for patients with severe corneal blindness from conjunctival scarring. Tooth-in-eye surgery remains a comparatively rare procedure even 60 years after its development, but advocates hope the newest success stories can help popularize the treatment option for some of the most difficult cases of blindness.

Pioneered by Italian ophthalmologist Benedetto Strampelli in the early 1960s, tooth-in-eye surgery is intended to minimize the risk of a patient’s body rejecting a foreign implant by mostly relying on its own biological material. Surgeons first extract a tooth (usually a canine), then shave it down to form a rectangular layer called a longitudinal lamina that includes a hole drilled in its center.

Once the frame is finished, doctors install a tiny plastic telescopic lens into the dentine case before temporarily sewing the implant into the side of a patient’s cheek, where it remains for a few months as new tissue grows around it. Another surgery removes the scar tissue from the patient’s eye and replaces it with healthy tissue also harvested from a cheek. In a final procedure, doctors sew the implant into the eye socket under the cheek tissue transplant, where the lens helps partially restore sight. Previous surveys indicate many patients’ vision improves enough to allow them to drive cars.

Tooth-in-eye surgery is only applicable for specific instances of severe corneal blindness, when trauma only damages the front surface of an eye and not its retina and optic nerves. This was the case for Brent Chapman, one of the three surgical patients profiled by the CBC program As It Happens last week. Chapman, a massage therapist from North Vancouver, lost his vision at age 13 after over-the-counter pain medication triggered a rare auto-immune reaction called Stevens-Johnson syndrome that resulted in a weekslong coma and severe burns across his body and eyes. Chapman, now 33, has since undergone roughly 50 surgeries including 10 corneal implants, but none managed to permanently restore his vision.

Due to the potential risks involved in tooth-in-eye surgery, physicians are only attempting the procedure on one of each patient’s eyes. But despite the potential complications, tooth-in-eye surgery maintains a high success rate across the 10 countries in which it has been performed. A 2022 study from Italy, for example, determined around 94 percent of implant recipients could still see even 27 years after their surgeries. Although Chapman admitted to feeling “a little apprehensive” after first learning about the option, a quick chat with a woman who successfully received the same treatment convinced him to volunteer.

“She had been completely blind for 20 years, and is now snow skiing,” he said, adding: “I know it sounds a little crazy and science fiction-y.”

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