Last year we learned that some patients, who were evaluated for a stroke or transient ischemic attack when they had come to the ER complaining of recurrent “temporary blindness” after checking their smartphone in the dark were suffering from a phenomenon, known as ‘smartphone blindness.’ This has also been experienced by many of us when we have the sensation of dimmed vision or poor visual acuity, feeling punished for peeking at our email when we should be sleeping.
But now we have a study suggesting vision loss could be permanent due to the blue light being emitted from our smartphones or laptops.
Researchers from the University of Toledo found blue light will react with retinal, an active form of Vitamin A, that can damage the nearby cells they are designed to stimulate when creating sight.
Researcher Kasun Ratnayake states, “If you shine blue light on retinal, the retinal kills photoreceptor cells as the signaling molecule on the membrane dissolves,” and since these cells do not regenerate they are gone for good.
Although a blue-light induced retinal activated cell could prove useful when fighting cancer, this finding is worrisome as millions of people, including children, look at their smartphone and tablet in the dark, depending on the blue light more and more to see their screens.
What is blue light?
Sunlight is made up of the spectrum of colors including red, orange, yellow, green, blue and purple. Blue light is a light along the spectrum that has shorter wavelengths and more energy than red, which has longer wavelengths. We receive most of our blue light exposure from the sun but we can be exposed as well through our smart devices, LED lights and CFL (compact fluorescent light) bulbs.
IMAGE FROM PREVENTBLINDNESS.ORG
Smartphone use linked to retinal detachment
Studies surfaced a few years ago where great lengths of smartphone use can cause retinal detachment. In these cases the layer of the retina which focuses images, detaches from the back of the eye, causing serious vision loss. Though there are treatments, if not treated early can cause permanent blindness in the affected eye since the retina loses its blood and oxygen supply when detached. A woman from China had been using her smartphone for 2-3 hours in the dark each night when this occurred.
Smartphones have also been linked to myopia, near-sightedness, and sleeping disorders as the blue light emitted from the screen can disrupt melatonin production.
A recent study found that 30% of adults spend more than 9 hours a day using their smartphone. Physicians recommend avoiding extended use, adjust settings to black text on white background, and with this recent case study, use both eyes to look at the screen when using the phone at night.
A study from the University of Exeter and Barcelona Institute for Global Health finds blue light exposure at night-time to increase the risk of breast and prostate cancer.
Blue light is emitted from artificial lighting, such as LED’s and smart devices, and has been linked in the past to cancer, heart disease, diabetes and obesity. Why? Scientists believe the blue wavelengths in the light disrupt our circadian rhythm, or our body’s biological clock, by suppressing the secretion of melatonin. Poor sleep, and unpredictable body cycles, can affect our metabolism, hence our weight, diabetes risk and cancer risk.
In this study, published in the journal Environmental Health Perspectives, researchers reviewed data of more than 4000 patients, between the ages of 20 and 85, from 11 different geographical regions. They found exposure to blue light at night doubled the risk of prostate cancer in men, and increased breast cancer risk in women by 1.5.
The Sun reports study author Dr. Alejandro Sánchez de Miguel is urging to reduce exposure to outside street lights and use orange wavelength light rather than blue.
“The take-home message is: Use warm orange lights where possible, and shutters and blinds to block street light.
“Also, our findings suggest reducing your night-time exposure to smartphones and tablets could help cut cancer risk.
How to protect your eyes by minimizing blue light exposure
The recommendation to not use your smart device at night may not be very practical for many. So here are some additional tips:
Increasing the size of the font helps your eyes since they don’t need to strain as much to read. Try to look at your smartphone with a distance of 1 1/2 feet. Blinking often helps rest the eyes as well and keeps them lubricated and moist.
Screen time should be limited in the evenings. Avoid computer/phone screens at least 2-3 hours before bed.
Although LED light bulbs are more energy-efficient, bedroom lighting may need to be swapped for softer bulbs.
If the weather permits, getting some night air and watching the stars may help stimulate one’s melatonin, allowing him/her to get sleepy.
Blue-blocking glasses may help limit exposure if night computer work cannot be avoided.
Additionally there are apps that allow a blue light filter on one’s phone screen.
Finally its good to use the 20,20,20 rule. After every 20 minutes of use, look away at something 20 feet away for 20 seconds. This may help avoid eye strain from excessive smartphone use.