Did you know that exposure to blue light at night, emitted by electronics and energy-efficient light bulbs, can be harmful to your health, or can it?
Time was when people spent their evenings in relative darkness, but not any more. It's estimated that people spend 10-1/2 hour a day gazing at computers, smartphones, tablets and televisions. That's bad for a number reasons and some claim one big reason is that we are exposing ourselves to blue light.
Blue light is a type of electromagnetic radiation with a very short wavelength that produces a high amount of energy. There are two sources of blue light, the sun and artificial that is emitted from LED lighting and from digital devices.
Of course, all light can damage your eyes under certain circumstances, but while some claim that there's no scientific evidence suggesting that blue light is harmful to our eyes, but many people still think it is, which is why blue light-blocking glasses are so popular. So do the glasses work? Some people swear by them.
On the other side of the blue light coin, some claim we may be paying a price for spending so much time peering at things emitting blue light. Note well...these sources use the word “may” as in if might be true. Then, again, it might not.
Blue wavelengths are beneficial during daylight hours because they boost attention, reaction times, and mood, but seem to be the most disruptive at night. And the proliferation of electronics with screens, as well as energy-efficient lighting, is increasing our exposure to blue wavelengths, especially after sundown.
At night, light throws the body's biological clock, aka the circadian rhythm, out of whack. Sleep suffers. Worse, research shows that it may contribute to the causation of cancer, diabetes, heart disease, and obesity.
Our close proximity to a device when viewing, especially over long periods of time, means that harmful blue light can affect our well-being.
We are born without any of the protective Ocular Lens Pigment in the eyes. OLP only begins to form in the lens of the eye in the late teens. At the same time, the amount of melanin gradually lessens. So, for children who have not reached their teens who are exposed to blue light should have their eyes protected.
Geezers beware! The eye defends itself from this blue light attack by selectively limiting the amount of blue light that reaches the retina, protecting it from age-related macular degeneration. AMD is an eye disease where central vision is lost. When we get older, the low levels of melanin and the replacement of the lens, due to cataracts, means that older patients are now exposed to higher levels of blue light with a greater risk of AMD.
Some studies suggest a link between exposure to light at night, such as working the night shift, to some types of cancer, diabetes, heart disease, and obesity. That's not proof that nighttime light exposure causes these conditions; nor is it clear why it could be bad.
It is known that exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms, and there's some very preliminary experimental evidence that lower melatonin levels might explain the association with cancer.
A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers gradually shifted the timing of subjects circadian rhythms and found their blood sugar levels increased, throwing them into a pre-diabetic state, and levels of a hormone that leaves people feeling full after a meal went down. But that study only involved ten people.
Even dim light can interfere with a person's circadian rhythm and melatonin secretion. Light at night is part of the reason so many people don't get enough sleep and researchers have linked short sleep to increased risk for depression, as well as diabetes and cardiovascular problems.
Harvard researchers conducted an experiment comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppressed melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much.
Researchers at the University of Toronto compared the melatonin levels of people exposed to bright indoor light who were wearing blue-light–blocking goggles to people exposed to regular dim light without wearing goggles.
The experiment suggested that blue light is a potent suppressor of melatonin. It also suggests that shift workers and night owls could perhaps protect themselves if they wore eyewear that blocks blue light. Inexpensive sunglasses with orange-tinted lenses block blue light, but they also block other colors, so they're not suitable for use indoors at night.
If blue light does have adverse health effects, then environmental concerns, and the quest for energy-efficient lighting, could be at odds with personal health.
Those new compact fluorescent light bulbs and LED lights are much more energy-efficient than the old-fashioned incandescent light bulbs, but they also tend to produce more blue light.
The coatings inside fluorescent bulbs can be changed so they produce a warmer, less blue light. LED lights are more efficient than fluorescent lights, but they also produce a fair amount of light in the blue spectrum.
A light researcher at John Carroll University in Cleveland, Ohio noted that ordinary incandescent lights also produce some blue light, although less than most fluorescent light bulbs.
It is recommended that you use dim red lights for night lights. Red light has the least power to shift circadian rhythm and suppress melatonin. You should also avoid looking at bright screens beginning two to three hours before bed. If you work a night shift or use a lot of electronic devices at night, consider wearing blue-blocking glasses. Expose yourself to lots of bright light during the day, which will boost your ability to sleep at night, as well as your mood and alertness during daylight.