It’s not easy to transplant a whole human eye. The surgery is difficult. And the eyes themselves start to degenerate as soon as they’ve left the body. When surgeons attempted it a few years ago, the newly-transplanted eye wasn’t able to see.
But researchers believe they might have a solution: a device that maintains and revives freshly removed eyeballs using a technique called perfusion. Perfusion works by providing surgically-removed organs with some of the oxygen and nutrients they typically get when they’re inside a body. Treated eyes don’t degrade as quickly, and appear to retain the ability to transmit electrical signals, and potentially see. The device could one day make eye transplantations a viable possibility.
“It’s really cool,” says Shannon Tessier at Massachusetts General Hospital, who was not involved in the research but studies perfusion of other organs. “It could be a new frontier for retina preservation.”
Pia Cosma at the Centre for Genomic Regulation at the Barcelona Institute of Science and Technology in Spain and her colleagues have spent years developing their device. The Eye-in-a-Care-Box (ECaBox), as they call it, delivers an oxygen-rich supply of fluid through the artery that normally supplies the eye with blood.
The eye itself sits on a “bed,” and excess fluids are drained away. And while the device itself is sealed to maintain a specific temperature and pressure, a clear window on its side allows researchers to study and image the eye while it’s inside.
Cosma and her colleagues started experimenting with pig eyes, which are anatomically similar to human eyes but easier to get hold of (the team got theirs from a local slaughterhouse).
Pig eyes that are kept at room temperature outside of the device start to degenerate pretty quickly. The team found that cells in the eye shrank, and the eyes started to lose their structure. Cooling the organs didn’t help preserve them, either—the eyes degenerated within 24 hours even when they were kept at 4°C (39°F).
But eyes kept in the EcABox fared much better. 24 hours later, tests suggested the prefused eyes were “significantly more viable” than eyes that hadn’t been maintained in the device.
The perfused eyes also seemed to be able to respond to light, suggesting they might technically be able to see if they were transplanted. Untreated pig eyes lost this ability as soon as they were removed from the animal. But it came back after about 15 minutes of perfusion, according to the scientists behind the work. A few of the treated eyes kept going for 10 hours or more.
Cosma and her colleagues described the work in a preprint article that has not yet been peer reviewed, and did not want to comment on the work.
After success with the pig eyes, the team members then tested their device on human eyes. They first collected 12 eyes from six people who had died. In each case, one of each pair of eyes was put in the device, while the other was not. Again, the perfused eyes did better—and their retinas were preserved.
Cosma and her colleagues hope that their device could offer scientists a new way to study eye treatments—one that doesn’t involve experimenting on living animals. They also hope that, with some improvements, the ECaBox might provide a way to maintain and revive donated human eyes for whole-eye transplantation.
Whole-eye transplants have been attempted in the past, mostly in research animals, with limited success. In May 2023, a team at NYU Langone transplanted an eye along with part of a face to a man who had survived a high-voltage electrical accident that resulted in the loss of much of the left side of his face, including his left eye, two years earlier. Although the man recovered well, he wasn’t able to see out of the transplanted eye.
We won’t know whether eyes treated in the ECaBox could do any better until they have been transplanted, says Tessier.
In the meantime, Cosma and her colleagues plan to use a newer version of their device to collect more human eyes for research. “We are planning to develop a portable, surgery-room ECaBox to minimize [degradation] in heart-beating donor eyes, when they become available,” they write.
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