Revived Human Retinas Show Light Response 10 Hours Post-Mortem

Recent research reveals that human eyes can function outside the body for up to 10 hours post-mortem—twice as long as previously understood. By providing blood and oxygen to the donor eye, it continues to respond to light while maintaining structural integrity and overall health.

According to Dr. Thomas Johnson from Johns Hopkins University, “This study marks a significant milestone towards potential whole-eye transplantation.” He emphasizes that achieving a mild response outside the body is a substantial achievement.

In the UK, over 1 million individuals face blindness or low vision. Conditions like age-related macular degeneration lead to irreversible damage in the retina, impacting vision.

Although corneal transplants can restore sight for many, treating retinal damage remains complex due to its integration with the central nervous system. In 2023, surgeries involving partial face and complete eye transplants occurred, but they failed to restore the recipient’s vision—highlighting challenges such as the retina’s susceptibility to ischemia.

Research from Eimear Byrne at Barcelona University of Science and Technology aimed to mitigate this ischemic damage. They developed an innovative perfusion system using a flexible tube to deliver blood supply to the eye and surrounding tissues.

Their method involved oxygenating donor eyes with a specialized device called the Eye-in-Care-Box, which automatically regulates pressure and flow. Their tests showed that perfused eyes maintained retinal structure and health for up to 24 hours, unlike non-perfused eyes that deteriorated rapidly.

In subsequent experiments with 36 more donor eyes, they found that 15 demonstrated light-responsive electrical activity similar to that in living individuals—extending post-mortem viability to 10 hours, twice the previously documented duration. However, the reasons behind the non-responsive retinas remain unclear.

Despite these advancements, crucial challenges persist, particularly in regenerating severed optic nerve fibers to enable vision transmission from the donor eye to the recipient’s brain. “Without this connection, visual information cannot reach the brain,” Johnson explains.

While this study paves the way for improving eye transplant outcomes, maintaining a healthy eye metabolism after death could enhance future vision restoration techniques and reduce the risk of ischemic injury to donated eyes.

Multiple organizations are investigating strategies for optic nerve regeneration, with some emphasizing the urgent need to integrate promising interventions for whole-eye transplantation. “We are at a pivotal moment for advancing whole-eye transplant research,” Johnson adds.

The Eye-in-Care-Box may also revolutionize the testing of vision-related treatments on human eyes, providing insights that are more directly relevant to human health than animal models. “This technology has immense potential in understanding biological processes and developing novel experimental frameworks for drug testing,” Johnson concludes.