Death is perhaps the strangest topic for humans to discuss. Even thinking about it is un-comfortable for some people.
To unravel the mystery behind it, researchers around the world are conducting scientific studies on death and getting amazing results, like when researchers capture brain waves during death of an individual & detect signs of high cognitive activites.
And now, a team of US scientists may have found a way to revive light in the human eye after death. According to a study published yesterday (May 11, 2022) in the journal Nature, the team managed to revive the connection between light-sensing neurons in the eyes of donor organs.
Overcoming oxygen deprivation
The team measured retinal cell activity in mice & humans shortly after death. Early experiments indicated that oxygen deprivation was an important factor leading to the loss of photoreceptors’ loss of communication with other retinal cells in retina.
To achieve their results, Anne Hanneken, Associate Professor at Scripps Research, procured organ donor eyes in less than 20 min after death. On the other hand, Frans Vinberg, an assistant professor at the John A. Moran Eye Center, developed a transportation unit to restore oxygenation and other nutrients to organ donor eyes. Vinberg also built a device that stimulates the retina and measures its electrical activity.
Utilizing these devices, the team restored a specific electrical signal seen in living eyes, also known as the “b wave” in the postmortem retinas. After being triggered by light, the postmortem retinas emitted particular b waves.
“We were able to awaken the photo-receptor cells in the human macula, which is the part of the retina responsible for our central vision & our ability to see fine details and colors,” said Fatima Abbas, biomedical scientist and lead author of the study.
Questioning the irreversible nature of death
The revived photoreceptors also offer hope for future transplants that could help restore vision in people with eye disease. However, the transplanted cells and patches from the donor retina must be seamlessly integrated into the existing retinal circuitry. This has been a difficult problem that scientists are working.
The study provides the first example of donoted eyes responding to light. This, therefore, raises questions about the irreversibility of death, which is partly related to the permanent loss of neural activity.