As people continue to spend more time than ever in front of their digital screens on a daily basis, questions of possible health and safety concerns have become more of a topic of conversation. It has also led to an increase in discussion about — as well as advertisements for — eyeglasses that filter blue light from digital devices.
But, do these blue light-blocking glasses serve a purpose and are they necessary to preserve your long-term eye health? We set out to answer these questions and provide alternative solutions to provide relief from digital-related eye strain.
What Is Blue Light?
The human eye sees objects and colors within the spectrum of visible light, or what you may know as ROYGBIV — red, orange, yellow, green, blue, indigo, and violet. The colors on the red end of the spectrum have longer wavelengths with less energy. The colors on the violet end of the spectrum have shorter wavelengths and higher energy.
Blue light has one of the shortest wavelengths among colors (400 to 550 nanometers), meaning it has more energy than most of the colors your eyes see. By comparison, red has a wavelength of around 700 nanometers.
The sun is the main source of blue light, but it is also emitted from artificial sources such as fluorescent lights and LED lights. LEDs are used in some televisions, and many electronics, such as smartphones, tables, and computers are backlit by LEDs. It is this use of LEDs in personal electronics that has raised concern about the impact of blue light on the eyes.
Does Blue Light Hurt Your Eyes?
People use digital devices more than ever. In fact, more than 80% of adults use electronic devices for at least two hours per day, and more than 65% use two or more simultaneously, according to research by The Vision Council.
These patterns have sparked conversations about whether the blue light from these devices can harm the eyes and heighten the risk for age-related macular degeneration and blindness.
In short, the answer is no. Blue light emitted from electronic devices is not enough to have an impact on long-term eye health.
The truth is we have much greater exposure to blue light from other sources, and electronic devices are less bright in comparison. Harvard Health notes how an iPhone, when used on the maximum brightness setting, has around 625 candelas per square meter. However, LED or fluorescent lighting can be twice as bright, and the sun has 10 times greater ambient illumination.
Therefore, the amount of blue light from electronic devices is not enough to cause physical harm. In fact, we need exposure to blue light. It acts as a stimulant and helps keep us awake during the day as part of our natural circadian rhythm. However, as the American Academy of Ophthalmology (AAO) notes, blue light exposure at night can keep you from falling asleep and thus disrupt your natural sleep cycle.
Do Blue Light Glasses Actually Work?
Any eye problems you may have from using electronic devices for hours is more likely a result of digital-related eyestrain — not blue light. Staring at screens causes you to blink less, which can cause eyestrain, headaches, blurred vision, or dry eye. In other words, eyestrain occurs due to how you use electronic devices, not from blue light. Therefore, filtering out blue light will not solve your problem.
In fact, the American Journal of Ophthalmology (AJO) published a double-masked, randomized controlled trial that found blue-blocking lenses did not alter signs or symptoms of eyestrain with computer use relative to standard clear lenses. This lack of evidence leads the AAO to recommend against the use of blue-light blocking glasses and instead recommends patients take steps to alleviate digital eye strain.
How to Fix Eyestrain
Digital-related eyestrain is often a result of poor viewing habits. Whether it is working on your computer for hours without a break or spending part of your day on a smartphone, these habits often prevent you from blinking as much as you should. Under normal circumstances, the average human blinks about 15 times every minute. That number decreases precipitously to blinking only five to seven times every minute when viewing digital screens, according to the AAO. Not blinking enough leads to lower tear film, which can then leave your eyes tired, strained, or result in dry eye.
To help combat eyestrain, the AAO recommends a simple “20-20-20” rule in which you look at an object 20 feet away for 20 seconds every 20 minutes. When sitting at a computer, make sure you are 25 inches from the screen (this is about the length of your arm). For phones and tablets, increase the screen contrast to combat eyestrain.
If you wear contact lenses, switch it up and wear glasses for a part of the day so your eyes can rest. Should you notice your eyes drying out, using artificial tears can help moisten your eyes.
For jobs that require prolonged computer use, you can ask your eye doctor if computer glasses are an option. Computer glasses have progressive lenses that allow you to focus on computer screens, and they should not be confused with non-prescription blue light-blocking glasses. Visit the DMEI Optical Shop at one of our four convenient locations to explore our eyeglass options.
As far as blue light exposure making it more difficult to sleep, there are measures you can take. For example, limit viewing bright screens that emit blue light two to three hours before bedtime. Should you view your phone or tablet at night, place it on night mode or night mode to limit screen brightness. The contrast of colors used in night mode can also help reduce eyestrain.
