Australasian Science: Australia's authority on science since 1938

Infrared Protects Eyes

By Stephen Luntz

A dose of near infrared light can protect the eyes of people exposed to bright light of shorter wavelengths.

“There’s a group of cells that look after our vision and work behind the scenes called Müller cells,” explains Ms Rizalyn Albarracin, a PhD student at The Vision Centre and the Australian National University. “They act to protect the retina by clearing toxins and inducing healing whenever there is injury to the vision cells.”

Unfortunately, “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 Müller cells can over-react by multiplying and forming scar tissue behind the retina,” Albarracin says. Cells close to the scar tissue stop working, and the scar blocks the blood supply to the outer retina, depriving other vision cells of glucose and oxygen. “As a result, more vision cells die, which in turn provokes Müller cells to work even harder, forming more scar tissues and setting up a vicious cycle.”

Albarracin found that exposure to infrared light at a wavelength of 670 nm suppressed the Müller cells, providing temporary protection. Just 3 minutes was required to protect mice, but Albarracin suggests that those anticipating exposure to dazzling light might seek treatment lasting 30 minutes. Potential beneficiaries include welders and other construction workers, film actors and anyone spending time under intense sunlight.

Albarracin’s supervisor, Dr Krisztina Valter, notes: “Near infrared therapy is very benign, easy to use and involves no discomfort to the patient. It is already approved by the US Food and Drug Administration for use in sports medicine, for hair loss and so on – so developing a novel therapeutic application for the eyes is likely to be less complex and protracted than, say, developing a new drug.”

While the mechanism for the process is not entirely understood, Albarracin notes that one of the molecules produced by cell mitochondria has an absorption peak at 670 nm, and exposure to light of this wavelength increases production of ATP, which is sometimes described as the currency of intracellular energy exchange.