Researchers have developed a microscopic electrical implant, tested in mice, which holds the potential to restore vision for people who have been blinded.

When blindness occurs due to eye damage, the brain’s visual cortex – that receives and processes signals from the eyes – can still be intact. Therefore, ‘sight’ can be improved by stimulating the visual cortex, through the use of a brain implant which allows the brain to generate images.

A new study from EARA member the Netherlands Institute for Neuroscience, the University of Freiburg, Germany, and the Chalmers University of Technology, Sweden, created an implant composed of thin threads of electrodes, each the size of a single neuron, and made of flexible polymer and metal – overcoming some of the issues with existing implants, such as being too large, corrosive or rigid.

When the device was implanted into the visual cortexes of mice (with normal vision), the animals reacted to the stimulation applied to their brains, and the implant also remained stable over time, even until the end of one mouse’s lifespan.

Maria Asplund, at Chalmers, said: “We now know it is possible to make electrodes as small as a neuron (nerve cell) and keep this electrode effectively working in the brain over very long timespans, which is promising since this has been missing until now.

“The next step will be to create an implant that can have connections for 1000s of electrodes.”