Gary Morgan, OD

Blue light can affect your sleep cycle

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This is a guest post by VSP Network Optometrist Gary Morgan.

Did you know that your use of smart phones, tablets and computers may be a risk factor in developing age-related macular degeneration and losing precious hours of sleep?

Blue Light is more effective than any drug, including caffeine, at keeping us awake. Did you know that more blue light is emitted from smart phones and tablet computers than from any other light source? Did you know that the World health Organization (WHO) has classified night shift work (including blue light exposure) to its list of known and probable carcinogens? Let me explain…

Just as our ears serve two functions, hearing and balance, so do our eyes. We see through light exposure to the rods and cones in our retina, but there is a second set of light receptors in the eye that allow us to determine day from night. These light receptors are especially sensitive to blue wavelength light, which regulates secretion of our sleep hormone, melatonin.

Consider this… blue light has the highest energy of visible light (think colors of the rainbow). So when the sun comes up, the blue part of the visible light the sun emits scatters among the atmospheric particles more than other colors turning the sky blue. Before electric lighting, we would wake up exposed to sunlight, suppressing melatonin, which would cause us to be awake and alert for the day. At the end of the day as the sun sets, our blue light exposure is diminished and melatonin is secreted, allowing us to fall asleep. When we began lighting our homes with incandescent light bulbs, this sleep-wake cycle was slightly extended, but not by much.

Fast forward to today… incandescent lights have been replaced by fluorescent and compact fluorescent bulbs in our offices and homes. We spend 8 or more hours per day in front of electronic screens that emit a high amount of blue light, especially concentrated when this screen is a smart phone or tablet computer since these are held close to our eyes. For kids, this screen to eye distance can be as close as 8 inches!

Our bodies have become confused. The light sensing cells in our eyes are telling our brains that it is perpetually daylight.  Melatonin is suppressed and we can’t sleep!  And what are the consequences of this?  Diabetes, heart disease, obesity, depression and cancer are a few possibilities. And what happens to children when they do not get enough sleep? (parents know this!) Hyperactivity, inattention, irritability; noticeably similar symptoms to ADHD.

Sleep is essential to our wellbeing. We must strive to decrease our blue light exposure after dark and avoid the unintended health consequences of technology. I advise my patients to turn off their electronic devices after dinner if possible, which usually elicits laughing or eye rolling… in our digital world, this is difficult. My next suggestion is to wear UNITY lenses with blue light protection. These lenses filter harmful blue light, which can also diminishes vision and contributes to macular degeneration, the leading cause of blindness for those over 55. Visit your VSP eye doctor and try a pair of UNITY lenses with blue light protection for yourself and your family. Rest easy…