Dark mode is one of the most popular features on smartphones. People use it to save battery life, lessen eye strain, and improve text readability.
Dark mode cuts glare and reduces blue light and both of those are helpful for your eyes. Let’s take a look at what blue light is.
In the 1660s Isaac Newton began experimenting with sunlight and prisms. He demonstrated that clear white light is composed of seven visible colors—red, orange, yellow, green, blue, indigo, and violet. Each color is a different wavelength.
“Blue light” includes the blue, indigo, and violet light of the visible light spectrum. Blue light, also known as high energy visible (HEV) light, has the shortest wavelength of visible light, and produces the highest amount of energy. Too much HEV blue light can have negative effects on the retina. The largest source of blue light is sunlight. Other sources are:
- Fluorescent light
- LED light
- LED television
- Computer monitors, smart phones, and tablet screens.
The blue light exposure from digital screens is very small compared to the amount of exposure from the sun. At least 100 times less. However, continual extended screen time might have detrimental effects on the retina, so it makes sense to take some preventative actions.
Sleep Cycle and the “night shift” Mode
But changing the setting on your iPhone to “night shift” in which the color temperature of the display shifts from blue toward yellow won’t help you get more sleep. Recent research showed that the night shift mode did not have a significant impact on the melatonin-induced sleep cycle.
Protecting Your Eyes from Blue Light
If you wear glasses, have the lenses coated with a light-adaptive photochromic coating. This type of coating blocks up to 35% of indoor blue light and when the lenses darken outside in the sun they block more than 85% of the blue light. The coating reacts to the levels of light in your environment and causes the lenses to shift between a dark tint and a clear mode to fit the blue light level.
If you don’t wear glasses, wear UV sunglasses when outside. Sunglasses labeled UV 400 provide nearly 100% protection from harmful ultraviolet light rays, blocking wavelengths up to 400 nanometers, including UVA and UVB rays. You can also get computer glasses that have a special blue-light filter coating. Another option is screen filters for your digital devices. There are blue-light screen filters for computer monitors, laptops, tablets, smart phones, and TV screens.
Blue light is Needed for Good Health
Blue light boosts alertness, helps memory and cognitive function, and elevates mood. People who suffer from seasonal affective disorder (SAD) which causes depression are helped by light therapy. Bright visible-spectrum light therapy has proven effective in the treatment of SAD and recent research suggests that blue-light wavelengths account for that effectiveness.