A Tooth Inside the Eye? It Sounds Crazy, But It Can Restore Sight

By Sistema ETAPAPublished on October 16th, 2025

Representation of the eye. Adapted from Servier Medical Art under the CC BY 4.0 license (https://creativecommons.org/licenses/by/4.0/), available at (https://smart.servier.com/smart_image/astigmatic-vision/)

Imagine someone telling you that, to see again, you would need to put a tooth inside your eye. It sounds like something out of science fiction or a horror movie, but this procedure exists and has a name: Osteo-Odonto-Keratoprosthesis (OOKP). This bizarre solution has restored sight to people who had been blind for years. It’s a story of medical ingenuity and courage, showing how biology and medicine can transform the unthinkable into reality.

Before understanding why putting a tooth inside the eye might make sense, it is important to remember: seeing is one of the most complex functions of the human body, the result of millions of years of evolution. Animals have developed different strategies to transform light into information, and from that, the brain creates the experience of seeing. An eye is not just a "camera"; it needs structures to capture light, mechanisms to focus the image, nervous tissue to convert photons into electrical signals, and finally, a brain that processes it all.

In the human eye, four structures are fundamental to this process. The retina acts as a sensor: it detects light and converts it into nerve signals, without which image perception is impossible. The vitreous humor, a transparent gel that occupies most of the eyeball, maintains the eye's shape and ensures that light reaches the retina clearly.

The lens is the internal structure that focuses external light onto the retina and can change shape, adjusting the focus for near or far. And the cornea, which covers the front of the eye like a transparent window, is responsible for part of the protection of the eyeball's interior. But if it becomes opaque, it is as if someone has painted the window black.

Failures in any of these parts can lead to blindness. If the retina degenerates, as in macular degeneration, or if the optic nerve is damaged by glaucoma, the information does not reach the brain. The same can happen when the visual cortex is affected by a stroke, for example, leading to cortical blindness. The vitreous humor can fill with blood or inflammatory deposits, blocking the passage of light.

The lens, in turn, can gradually lose transparency in a process known as cataracts, a problem that usually affects the elderly and can be treated with replacement surgery using an artificial lens. Finally, the cornea can also be damaged by burns, trauma, autoimmune diseases, or severe infections. In these two situations, the blindness does not come from the sensor, but from a physical barrier that prevents light from entering. It is like having a perfect camera, but with the lens covered in mud. Corneal transplant is the standard treatment in these cases and usually restores vision with great success. But when the eye is already inflamed, full of blood vessels, or has undergone several previous transplant rejections, the chances of success drop drastically. In this scenario, insisting on new transplants usually fails. This is where OOKP comes in, as a last resort to restore sight.

The OOKP procedure occurs in four well-defined phases:

In the first phase, surgeons remove a canine tooth from the own patient. The choice is not random: the canine is more robust and long, allowing a firm block to be sculpted, which is suitable for receiving an acrylic micro-lens. This block undergoes meticulous modeling to become a biological "lens holder," simultaneously resistant and biocompatible.
In the second phase, this tooth-bone-lens assembly is implanted under the cheek skin. This seemingly strange step has a crucial goal: to allow the implant to become vascularized, receiving blood vessels and transforming into living tissue. This greatly increases the chance that the eye will later accept the implant. The cheek is chosen precisely because it is an accessible and well-irrigated site, functioning as a natural incubator.
While the block matures in the cheek, the third phase takes place: the preparation of the eye. The scars and opaque areas of the cornea are removed, and the eyeball is covered with grafts of oral mucosa, tissue adapted to humid environments and resistant to constant aggressions. This replacement creates a stable ocular surface capable of protecting the future implant.
Finally, in the fourth phase, after a few months, the block is removed from the cheek and fixed in the center of the eye. Surgeons open a small window for the lens, leaving it exposed while the rest is protected by the mucosa. Light, which was previously blocked by the destroyed cornea, now passes through the lens and reaches the retina.

In Canada, Mount Saint Joseph Hospital performed the country's first OOKP surgeries. Gail Lane, blind for a decade due to autoimmune scars, said after the surgery: 'I thought I would never see the colors of the sunset again. Now, I can see them, and it's wonderful.' Brent Chapman, who lost his sight in his teens, described: 'It’s like being reborn into the world. I can see the faces of the people I love, I can watch a hockey game again.'

But it is not a technique for every patient. OOKP is only attempted when all corneal transplants have failed or have a very high chance of failing. It is a complex surgery, performed only in highly specialized centers, which requires lifelong monitoring and carries risks, such as glaucoma or retinal detachment. It’s, therefore, an extreme resource for delicate situations.

Putting a tooth in the eye sounds bizarre, but it reveals the innovativeness of modern medicine. By using the patient's own living tissue as a support for a lens, doctors can restore the passage of light when the cornea is beyond recovery. For those who spent years in blindness and without hope, it is more than a curious scientific fact: it is a new beginning.

And what does all this have to do with Etapa SigmaCamp?

Students who participate in this scientific immersion experience intense days of learning, discovery, and challenges. More than cutting-edge content in biology, physics, chemistry, technology, and other areas, they develop discipline, persistence, and, above all, curiosity.

These qualities are the fertile ground from which the innovations of the future sprout. After all, what seems impossible today may be the transformative solution of tomorrow—provided there are minds prepared to ask, persist, and experiment.

And you? What will your great discovery be?