Scientists in the US have brought back to life dead eyes from organ donors in a breakthrough which hints that brain death could be reversible.
The discovery that eyes taken from organ donors five hours after death responded to light “raises the question of whether brain death, as it is currently defined, is truly irreversible," the researchers said in a study published in Nature.
Brain death is a condition when someone is no longer able to survive without life support and is unable to breathe on their own. It is considered irreversible and the person is declared dead.
According to the scientists, their study proved that photosensitive cells in the retina can respond to light and sending signals “resembling those recorded from living subjects” to each other even five hours after death.
“We were able to wake up photoreceptor cells in the human macula, which is the part of the retina responsible for our central vision and our ability to see fine detail and colour," lead researcher Dr Fatima Abbas from University of Utah told The Telegraph.
“In eyes obtained up to five hours after an organ donor’s death, these cells responded to bright light, coloured lights and even very dim flashes of light.”
Dr Frans Vinberg, an assistant professor of ophthalmology and visual sciences at the University of Utah, said, "We were able to make the retinal cells talk to each other, the way they do in the living eye."
"Past studies have restored very limited electrical activity in organ donor eyes, but this has never been achieved in the macula, and never to the extent we have now demonstrated," he told The Telegraph.
Adding to this, Dr Sam Parnia, an expert in near-death experiences, said, “This fascinating study clearly demonstrates that by contrast to social and historical convention, whereby death is considered permanent and irreversible, from a biological perspective, death remains reversible well into the post-mortem period."
The researchers are hopeful the breakthrough will speed up new therapies for loss of vision and improve the understanding of neurodegenerative diseases.
“The scientific community can now study human vision in ways that just aren’t possible with laboratory animals,” said Dr Vinberg. “We hope this will motivate organ donor societies, organ donors, and eye banks by helping them understand the exciting new possibilities this type of research offers.”