Transplant surgeons have long mastered procedures for hearts, lungs, and kidneys, yet the whole eye remains an elusive target for successful transplantation. The extracted eyeball rapidly loses oxygen, causing light-sensitive retinal cells to die before surgeons can even prepare the organ for surgery. In a groundbreaking development, an experimental perfusion device has enabled biologists to slow tissue degradation and preserve the light response in pig eyes for up to 10 hours after the animal’s death.
The ECaBox Perfusion System
The device, named Eye-in-a-Care-Box (ECaBox), features a 3D-printed housing that holds the extracted eye. A flexible tube is inserted into the ophthalmic artery, and a pump continuously delivers an oxygenated nutrient solution while sensors regulate pressure and flow rate. This artificial circulation mimics the blood supply that normally nourishes ocular tissues during life.
Retinal Vulnerability and the 2024 Transplant Milestone
The retina—a thin layer of neural tissue lining the back of the eye—converts light into electrical signals that travel via the optic nerve to the brain. Even brief interruptions in blood flow damage this complex structure, sharply reducing transplant viability. Interest in eye transplantation surged after a 2024 procedure in which a man received a combined face and left-eye transplant following severe electrical trauma. Although vision did not return, the donor eye regained blood flow and retained retinal light responses, proving that reperfusion is possible but underscoring the remaining hurdle of optic-nerve reconnection.
Experimental Design and Pig-Eye Results
After the clinical case, researchers tested whether whole-eye preservation ex vivo could extend the window for potential transplantation. Pig eyes obtained from a nearby slaughterhouse were placed on ice and delivered to the lab within 2.5 hours of death. One group was connected to ECaBox; controls were stored at 4 °C without perfusion. After 24 hours, ECaBox eyes showed markedly better preservation of cells and vessels. In 90 % of correctly cannulated specimens, colored dye confirmed uniform perfusion through arteries, veins, and capillaries. Electroretinography detected electrical responses to light flashes in 15 of 36 perfused eyes, with several still reactive 10 hours post-mortem. Responses faded once the pump was stopped, confirming that the oxygenated solution sustained cellular function.
Timing and Human-Eye Validation
Delay proved critical: initiating perfusion more than five hours after death caused significantly greater vascular damage. The team then evaluated 12 human eyes from six post-mortem donors; one eye per pair received ECaBox support while the other served as a control. Perfused human specimens again demonstrated superior tissue architecture and cell viability, although electroretinography was not performed due to ethical and logistical constraints.
Future Applications and Remaining Challenges
Developers envision a portable operating unit that would allow immediate cannulation beside the donor, minimizing ischemic time. While ECaBox cannot yet solve optic-nerve regeneration—necessary for image-forming vision—it offers immediate value for studying retinal diseases such as age-related macular degeneration. Large-animal eyes preserved ex vivo provide access to the macula, absent in rodents, enabling drug testing without live-animal procedures. Further work will determine maximum preservation duration and confirm light responses in rapidly connected human retinas.
