Blue light can have a worrying effect on our eyes, literally killing the cells in our retinas. Now, researchers from the University of Toledo have discovered exactly why this is, publishing their findings in the journal Scientific Reports.
“We are being exposed to blue light continuously, and the eye’s cornea and lens cannot block or reflect it,” study author Dr Ajith Karunarathne said in a statement. “It’s no secret that blue light harms our vision by damaging the eye’s retina. Our experiments explain how this happens, and we hope this leads to therapies that slow macular degeneration, such as a new kind of eye drop.”
Macular degeneration, sometimes referred to as age-related macular degeneration or AMD, is a condition that results from the breakdown or thinning of cells in the macula – a part of the eye’s retina that’s important for seeing fine details. The light-receptive cells in the macula of those with AMD die off, leading to serious vision problems.
Unfortunately, there’s currently no cure for AMD, although certain treatments like eye injections can help slow down its progression. The disease tends to occur in middle to old age and is responsible for roughly half of cases of impaired vision.
So where does blue light come in?
Well, it’s all to do with a molecule called retinal, which helps cells in the retina to sense light and relay visual information to the brain. When exposed to blue light, retinal turns on the eye, killing vital light-sensing cells. This is because the blue light causes it to trigger a series of reactions – a molecule in the affected cell’s membrane distorts, then an increase in calcium changes its shape, and the cell dies. The damage is permanent.
“Photoreceptor cells do not regenerate in the eye. When they’re dead, they’re dead for good,” said Karunarathne.