Until the invention of artificial lighting, the sun was the primary source of lighting and people spent their evenings in relative darkness.
Now, evenings are generally illuminated, and we take that artificial lighting pretty much for granted. Research is telling us that there is a price for the benefits derived from the extended light we enjoy on a regular basis.
Such extended light effects our biological clock by impacting our circadian rhythm. This has been shown to have an adverse effect on sleep and may contribute to the development of such diseases as cancer, diabetes, heart disease and obesity.
What is blue light?
White light is comprised of a spectrum of colors (red, orange, yellow, green, blue, indigo and violet). Each color has its own wavelength. Not all colors have the same effect. Blue wavelengths, which are beneficial during daylight hours because they boost attention, reaction times and mood, are disruptive at night. Making things much worse is the proliferation of electronics with screens and energy efficient lighting which greatly increase our exposure to blue wavelengths.
Light and sleep
Daylight keeps a person’s internal clock aligned with the environment. Exposure to light suppresses the secretion of melatonin, a hormone that influences circadian rhythms. Light at night is part of the reason so many people do not get enough sleep.
While light of any sort can suppress the secretion of melatonin, blue light at night does so more powerfully. Decreased restful sleep has been linked to increased risk for depression, and such medical issues as diabetes and cardiovascular problems. Generally speaking, a lack of restful sleep can have a negative effect on all sorts of cognitive, emotional and behavioral functions.
Some steps to consider
- Minimize your use of electronic screens (e.g., computer, smart phone) after dusk.
- If you must use electronics, install an app that reduces the blue light emanating from a device.
- Consider the use of blue light blocking glasses
- Expose yourself to lots of bright light during the day which will improve your mood and alertness during the day and increase your ability to sleep at night.
If you are considering the use of blue light blocking glasses to decrease the negative effect of blue light exposure, here are some points to consider.
- Not all blue light blocking glasses are the same. Do your due diligence and make sure the glasses you buy have been researched to prove they do block blue light.
- Glasses will vary in the amount of blue light they block. For example, some people recommend wearing glasses that block 50% of blue light if worn during the day and 75-95% blockage when worn in the evening/night.
- While orange or brown tinted lenses are known to block blue light, the color of the lenses does not necessarily correlate with the blue light blocking effectiveness. For example, you can get clear lenses that have been treated to block blue light.
- You can buy prescription lenses with blue light blocking capability. See your optometrist.
- Do not wear the blue light blocking glasses all day. Allow yourself to get blue light (especially natural light) in the morning. Consider wearing the glasses as the day goes on, especially if you are doing a lot of screen time. As evening occurs and two to three hours before bed is the main time to use blue light blocking glasses if electronic screens are being used.
- Whenever possible try to keep at least two feet from the screen you are viewing as this reduces the amount of blue light reaching your eyes.
- To help with eye fatigue with or without the blue light glasses, get in the habit of periodically looking away from the screen and looking at a distance. This allows the eye muscles to relax. Also, if possible, look at the color green. Green is in the middle of the spectrum so the eyes strain least when looking at green.
If you have any questions or if you have tried blue light glasses and and still have concerns, contact Sadar Psychological and Sports Center, we will be happy to help you.