In the modern world, understanding the effects of blue light exposure has become increasingly important. While blue light has always been around as a natural component of sunlight, excessive exposure to artificial blue light through technology has been known to impact our health.
As a source of visible light, blue light is measured on the electromagnetic spectrum, which is made up of different sources of energy as light. This includes x-rays, microwaves, radio waves, visible light, etc. Visible light is the only source of the electromagnetic spectrum that humans can see. On the electromagnetic spectrum, visible light appears between 400 and 700 nanometers – each color has its own measurement of visibility. Blue light is known to have a shorter wavelength, which means it has a higher energy and therefore more potential to cause harmful effects on the eyes.1
One commonly misunderstood fact about blue light is that the strongest and most powerful source of blue light is from the sun, not digital devices. For example, the difference between exposure to blue light from the sun vs. exposure to blue light from digital screens is described below:
- A smart phone emits 0.0013 watt/m2 at 435nm
- The sun emits 0.175 watt/m2 at 435nm
This means that a person on their smart phone would need to be on their device for over two hours to receive the same amount of blue light exposure as someone sitting outside in the natural sunlight for one minute.
The strength of blue light causes damage to the eyes as it passes through the cornea, the lens, and then reaches the retina. When the retina is damaged this in turn can cause damage to your vision. Some conditions that can be caused by a damaged retina include age-related macular degeneration, cataracts, eye cancer, and growths on the clear part of the eye3.
In addition to physical damage to the retina, prolonged exposure to blue light through screens without taking proper breaks can also cause eye strain, fatigue, dry eyes, irritated eyes, headaches, and even disruption to sleep patterns.4
Knowing that the main source of blue light is the Sun, the best way to protect your vision is to wear sunglasses when outside and to avoid staring at a sunny sky. Other ways to prevent harm from blue light exposure are to limit screen exposure, adjust the brightness on your devices, and take regular breaks from digital devices by using the 20/20/20 rule – stop every 20 minutes to focus on objects that are 20 minutes away for about 20 seconds before going back to your digital screen4.
While it is very difficult in our modern world to completely prevent exposure to blue light, it is possible to use protective measures to shelter your eyes. Understanding the effects blue light can have on your eyes over time can help us all learn to be more aware of our ocular health.
Sources:
1: https://www.webmd.com/eye-health/what-is-blue-light
2: https://jamanetwork.com/journals/jamaophthalmology/fullarticle/416298
4: https://www.healthline.com/health/what-is-blue-light#risks-and-side-effects