Light is made up of electromagnetic particles that travel in waves, emit energy, and range in length and strength. The shorter the wavelength, the higher the energy. Different wavelength categories are - gamma rays, x-rays, ultraviolet rays, visible light, infrared light, and radio waves.  Together these wavelengths make up the electromagnetic spectrum. However, the human eye is sensitive to only one part of this spectrum -  visible light, that part of the electromagnetic spectrum seen as colors: violet, indigo, blue, green, yellow, orange, and red.  Blue light has a very short wavelength, which produces a higher amount of energy. Studies suggest that, over time, exposure to the blue end of the light spectrum could cause significant long-term damage to your eyes.

What is blue light?

Blue light is everywhere. As sunlight travels through the atmosphere, the shorter, high-energy blue wavelengths collide with the air molecules causing blue light to scatter around, giving the sky its blue color. Exposure to blue light during daytime hours helps maintain a healthy circadian rhythm, the natural sleep-wake cycle. Dr. Charles Czeisler has demonstrated that daylight keeps a person's internal clock synchronized with the environment. Too much exposure to blue light late at night can disrupt the sleep-wake cycle, causing problems sleeping and daytime tiredness. However, under exposure to sunlight in children adversely affects eyes and vision’s growth and development. Few studies show a deficiency in blue light exposure could contribute to the recent increase in nearsightedness. 

Blue light helps boost

• alertness

• memory and cognitive function

• reaction times

• elevate moods

• the feeling of well being. 

With the evolution in digital screen technology, devices use LED backlight technology to enhance screen brightness and clarity. These LEDs emit powerful blue light waves. Blue light waves are among the shortest, highest-energy wavelengths in the visible light spectrum. Because they are shorter, these "Blue" or High Energy Visible (HEV) wavelengths flicker more easily than longer, weaker wavelengths. Flickering creates a glare that can reduce visual contrast and affect sharpness and clarity. This flickering and glaring may be one reason for digital eye strain, headaches, physical and mental fatigue caused by many hours sitting in front of a computer screen or other electronic device.  

Our eyes' natural filters do not entirely protect against blue light rays from the sun, let alone the blue light emanating from these devices or fluorescent-light tubes. Prolonged exposure to blue light may cause retinal damage and contribute to age-related macular degeneration, leading to loss of vision.

Some studies suggest a link between exposure to light at night, such as working the night shift, to 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 for us. A Harvard study shed a little bit of light on the possible connection to diabetes and possibly obesity. The researchers put ten people on a schedule that gradually shifted the timing of their circadian rhythms. Their blood sugar levels increased, pushing them into a prediabetic state, and leptin levels (satiety hormone) went down.

Melatonin is a hormone that the brain produces in response to darkness, helping with circadian rhythms and sleep. Exposure to light, even dim light, suppresses the secretion of melatonin, disrupting sleep. Light at night is why so many people don't get enough sleep, and researchers have linked short sleep to increased risk for depression and diabetes, and cardiovascular problems. While the light of any kind can suppress melatonin secretion, blue light at night does so more powerfully. Harvard researchers and their colleagues experimented comparing the effects of 6.5 hours of exposure to blue light to exposure to green light of comparable brightness. The blue light suppresses melatonin for about twice as long as the green light and shifted circadian rhythms by twice as much (3 hours vs. 1.5 hours).

Protect yourself from blue light

There are a few ways to decrease exposure to blue light:

• Use dim red lights for night lights. Swap out fluorescent/LED night lights in bedrooms and bathrooms for dim red lights, which have the least effect on melatonin and circadian rhythms.

• Avoid looking at bright screens beginning two to three hours before bed.

• If you work a night shift or use many electronic devices at night, consider wearing blue-blocking glasses or installing an app that filters the blue/green wavelength at night.

• 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.

• Computer glasses with yellow-tinted lenses that block blue light can help ease computer digital eye strain by increasing contrast. Wear computer glasses while on a device for two or more hours.

• Anti-reflective lenses reduce glare and increase contrast and block blue light from the sun and digital devices.

• Clean Your Screen. A dust-free, smudge-free screen helps reduce glare.

• Adjust screen brightness, change background color from bright white to cool gray. 

• Take frequent breaks and move away from the screen. 

• Those who smoke are up to 4 times more likely to go blind in old age. If you are a smoker, kick the habit to preserve your vision.

• Remind yourself to blink more often. Staring at a digital screen can affect the number of times you blink, causing eyes to dry. Use artificial tears when your eyes feel dry.

• Eliminate screens in bedrooms overnight. (You might need to buy an alarm clock).

• Avoid device multi-tasking, especially while trying to learn or work from home. Jumping between screens and apps makes work take longer. Turn off notifications for all but the essential apps. Use your phone. Don’t let it use you.

60% of people spend more than 6 hours a day in front of a digital device. The ‘virtual’ life during the current pandemic can leave us with screen fatigue and craving human connection. I’ve realized with clarity in these dark, anxious times that so many of our problems with technology don’t emanate from digital screens. Instead, it is from the disruption and alienation that creeps into our relationships with ourselves and others as we allow our experiences and challenging emotions to be mediated, numbed out, blurred by digital media. The phone is like a fentanyl lollipop; yes, it’s possible to abuse, but our pain, and the massive pain of the world driving us to it, is arguably the real problem. The antidote is reconnecting to our bodies and our feelings, with the assistance of loved ones who make it safe to do that.

References:

https://pubmed.ncbi.nlm.nih.gov/21600300/

https://pubmed.ncbi.nlm.nih.gov/25535358/

Published 11/28/2020

About Us

Dr. Amar Singh, MD, and Dr. Poonam Singh, MD, are board-certified by the American Board of Internal Medicine and American Board of Obesity Medicine. They specialize in preventing, treating, and reversing chronic diseases using an evidence-based holistic approach. They are specifically interested in weight management, hormone re-balancing, and longevity. The American College of Physicians has recognized them as Fellows, FACP,  for their excellence and contributions made to both medicine and the broader community. They enjoy teaching, volunteering, and advocating for their patients. Their mission is to share simple, effective, and proven strategies that lead to meaningful, sustainable, and long-lasting well-being.