Getting a tooth implanted in the eye, why? 👀

A tooth to restore vision: what seems like something out of a science fiction novel is, in fact, a medical reality. A rare procedure, called osteo-odonto-keratoprosthesis (OOKP), uses a tooth to support an optical lens and restore sight to people suffering from severe corneal blindness.

A two-step procedure

OOKP is a procedure that takes place in two distinct phases, spaced several months apart. The first step involves extracting a tooth from the patient, usually a canine, and shaping it to insert a plastic optical lens (concretely, the tooth is carved into a rectangle and then drilled with a hole to accommodate the lens). This modified tooth is then temporarily implanted into the patient's cheek, where it develops new tissue and vascularization.

Meanwhile, the eye is prepared to receive the implant. Surgeons remove scar tissue from the cornea and replace it with a graft of oral tissue, taken from inside the cheek. This graft creates a favorable environment for the future implantation of the tooth.

The second step takes place about three months later. The tooth, now covered with living tissue, is removed from the cheek and transplanted into the eye. The optical lens, integrated into the tooth, restores vision. This ingenious approach exploits the biocompatibility of dentin and minimizes the risk of rejection.

Promising results despite the risks

OOKP shows impressive success rates. An Italian study published in 2022 found that 94% of patients retained their vision 27 years after the procedure. These results make it a viable option for people suffering from severe corneal blindness, particularly those with autoimmune diseases or chemical burns.

However, this procedure is not without risks. Potential complications include infections, postoperative issues, and, in rare cases, total vision loss. These factors make it a last-resort solution, reserved for patients for whom other treatments have failed.

For these patients, the risks are largely outweighed by the hope of regaining their sight. OOKP represents a unique opportunity to return to a normal life, with simple activities like reading or traveling.

To go further: Why use a tooth in this surgery?

The use of a tooth in OOKP relies on unique biological properties. Dentin, the main material of teeth, is both strong and biocompatible, making it an ideal support for an optical lens. This durability allows the implant to last for decades without degrading, a major advantage for patients.

Moreover, the tooth is an autologous tissue, meaning it comes from the patient themselves. This almost entirely eliminates the risk of rejection, unlike synthetic implants or grafts of foreign tissue. The biocompatibility of dentin also facilitates the integration of the implant into the eye, reducing postoperative complications.

The choice of a tooth is explained by its ability to develop new tissue and vascularization when implanted in the cheek. This process, called neovascularization, prepares the tooth for its future role in the eye. Once transplanted, it acts as a stable and natural structure to support the optical lens.

This combination of strength, biocompatibility, and integration capacity makes the tooth an ingenious choice for this surgery. Although surprising, this approach demonstrates how the resources of the human body can be harnessed for innovative medical solutions.