Infrared light stops eye damage caused by bright lights

Sydney - Treating eyes with gentle infrared light can help prevent damage caused by subsequent exposure to bright light, says a study.

A breakthrough by The Vision Centre at the Australian National University can protect the vision of people exposed to bright sunlight or artificial lights, namely construction workers, sportspeople, fishermen, farmers, welders, actors, entertainers and others.

Krisztina Valter and doctoral researcher Rizalyn Albarracin at The Vision Centre have shown that pre-treatment with near infrared light (NIR) prevents a build-up of scar tissue in the retina causing subsequent harm to sight, the journal Photochemistry and Photobiology reported.

"There's a group of cells that look after our vision and work behind the scenes called Muller cells," said Albarracin. "They act to protect the retina by clearing toxins and inducing healing whenever there is injury to the vision cells."

"However, their protection is a double-edge sword for the eyes. When the retina comes under extreme stress, as when it is exposed to intensely bright light and loses a large number of vision cells, the Muller cells can over-react by multiplying and forming scar tissue behind the retina," she said, according to a university statement.

"When this occurs, two things happen: first, the vision cells close to where the scar tissue forms will stop working. Secondly, the scar tissue blocks the blood supply to the outer retina, so that other vision cells are starved of oxygen, glucose and other nutrients vital to their survival," said Albarracin.

"As a result more vision cells die, which in turn provokes Muller cells to work even harder, forming more scar tissues and setting up a vicious cycle," added Albarracin.

"We found that the treatment with mild NIR successfully inhibits the Muller cells from multiplying and forming scar tissue," said team leader Valter.

Researchers used an array of small LEDs (light emitting diodes) that have been tuned to produce near infrared light at a specific wavelength - 670 nanometres.