Study finds way to ‘reboot’ eye, restore impaired vision

 Scientists claim to have found a way to restore vision in people with a common developmental eye disorder by “rebooting” the retina to its early state, enabling it to grow and cure itself. 

Researchers at the Massachusetts Institute of Technology in the US found that temporarily anesthetising the retina could reverse the vision system to an early state, curing a condition known as amblyopia or “lazy eye”. 

In people with amblyopia, vision in one or both eyes does not develop properly during childhood as the brain learns to ignore one of the eyes. 

Current treatments are only effective during infancy when nerve connections are still being formed. 

The MIT researchers found that anesthetising the retina of the amblyopic eye in mice for a couple of days restored the brain's visual response to that eye even in adulthood, according to a study published in the journal Cell Reports. 

In future studies, they hope to show the treatment also works in other animal species and ultimately humans. 

“If it does, it is a pretty substantial step forward because it would be reassuring to know vision in the good eye would not have to be interrupted by treatment," study author Mark Bears argued. “The amblyopic eye, which is not doing much, could be inactivated and 'brought back to life' instead.” 

The researchers focused on a network of brain nerves, called the lateral geniculate nucleus, which relays information from the eyes to the visual cortex where vision is processed. 

In 2008, researchers had found blocking signals from the retina of an eye to nerves in the network caused those neurons to fire synchronous "bursts" of electrical signals to nerves in the visual cortex. 

The latest study tested whether those bursts of signals played a role in potential amblyopia treatments. 

They injected anaesthesia into the eyes of amblyopic mice and compared them with a control group. They found the injection took the retina offline for two days. 

The researchers then measured activity in the neurons of the visual cortex to find the ratio of signals from each eye. 

The signal ratio was much higher in mice that received the treatment compared to those left untreated, hinting that the injection could “reboot” the eye. 

This suggested that after the amblyopic eye was anesthetised, its input in the brain rose to parity with input from the normal eye. 

“We are cautiously optimistic that these findings may lead to a new treatment approach for human amblyopia, particularly given the discovery that silencing the amblyopic eye is effective," the researchers said in the study. 

WAM