Medical Breakthrough: World’s First Eye Transplant Marks a Milestone in Medicine
New York surgeons performed the world’s first eye transplant. Before this pioneering procedure, doctors had focused solely on transplants of the cornea – the transparent front layer of the eye. Mario Luiz Monteiro, doctor at the Department of Neuro-ophthalmology at the USP Faculty of Medicine, explains the progress made by doctors.
The procedure
The patient suffered a severe electrical shock and the team’s goal was to fill the eye and perform facial reconstruction. According to Monteiro, plastic surgeons have been performing facial transplants for some time, even in the subcutaneous regions. The advantage of this procedure is that the pre-existing nutrition of the face allows the new grafts to receive irrigation.
However, the organ of vision is more complicated than the skin. “The eye, in addition to seeing, needs to form an image focused on the retina and transmit this image to the brain. But it needs irrigation to stay alive. In other words, the retina needs blood to stay alive; It’s like the Central Nervous System, if it runs out of blood for a few minutes, it dies”, explains Monteiro. Furthermore, the doctor also comments that the anterior part of the eye also needs blood to produce aqueous humor, responsible for maintaining the organ’s tone.
Monteiro highlights that the transplant carried out was not just of the eye organ: the professionals also transplanted part of the face and the tissues surrounding the eye – the orbit. “With this, they took all the structures, and what they did innovatively was to prove that they can keep the eye viable; that is, they separated an artery from the patient’s temple and before fitting the graft into the recipient, they connected this temporal artery to the artery that nourishes the eye,” he points out.
The artery responsible for nourishing the organ, the retina and the optic nerve is located at the bottom of the orbit and is called the ophthalmic artery. When the injured eye is removed, irrigation is lost. In this way, the doctor explains that, the moment another organ was implanted, he would die. The pioneering nature of the procedure, therefore, lies in the novelty of the connection with the temple artery, which kept the eye nourished and viable.
According to Monteiro, the transplanted eye functions as a biological prosthesis, but is not yet capable of forming and transmitting images. “The image is formed on the retina and is transmitted by the optic nerve – which are wires that leave the retina and are connected to the brain”, he explains. In the case of the patient, these wires are not connected, because the technology to make this connection is not yet available.
Recovery
There are other lines of research that seek to restore vision in blind eyes, such as inserting electrodes into the cortex. “The back of the brain is the part that actually sees. Then, you place the electrodes, pass a wire subcutaneously and place a camera, which connects with the electrode under the skin near the ear. The visual stimulus that this camera captures goes directly to the electrode in the brain”, explains the doctor. This procedure, according to Monteiro, concerns the resolution of motor issues. In the visual part, however, the complexity is immense, due to the amount of information needed to produce colors, contrasts and shapes.