Blue light occurs naturally, but it also comes from computer and device screens. Energy-efficient lighting, particularly LED bulbs, is another common source of blue light. In today’s digital, well-lit world, most people are constantly exposed to this type of light, which can bring both benefits and drawbacks.
Light gets measured in wavelengths using a tiny unit called nanometers (nm). One nm is one-billionth of a meter. Shorter wavelength light has more energy. Blue light is at the short end of the visible light spectrum, with wavelengths of 450 to 495 nm. In contrast, red light has much longer visible wavelengths, at 620 to 750 nm.
Because of its high energy, blue light is often associated with a disruptive effect on sleep patterns. At the same time, it also brings benefits, such as a heightened sense of alertness.
The exact impacts of blue light can vary depending on a variety of factors. It is essential for people to figure out how to relate to this type of high-energy light so that they can take advantage of its benefits and avoid a negative impact on their health.
What are the health benefits of blue light?
Blue light brings several health benefits. There is no evidence to suggest that blue light improves health over the long term, but studies have linked exposure to short-wavelength light with positive short-term effects.
Here is a look at three of the benefits of exposure to blue light.
Improved cognition
A study by the Sleep Research Society found that subjects exposed to blue light during certain activities were able to complete their tasks faster than those whose workspace was illuminated by other light wavelengths. Scans also showed increased activity in certain areas of the brain.
In the study, participants were exposed to blue light for 30 minutes, so there was no data associated with long-term exposure, which someone might experience when working on a computer screen for hours at a time.
However, the study did provide evidence that controlled blue light exposure can improve brain performance.
Improved memory
In addition to brain activity, blue light can improve memory. Another study found that subjects were able to perform memory tasks better after 30 minutes of exposure to blue light. Because of the controlled nature and timeframe of the study, more research is likely necessary to provide a more solid link between 400 nm light wavelengths and improved memory.
Elevated mood
Blue light can affect certain bodily functions, such as hormone production, that can affect mood.
Blue light, along with other wavelengths, is essential for treating seasonal affective disorder (SAD), which affects people in four-season climates during the winter. In addition to aiding hormone secretion, it helps people maintain a normal sleep-wake cycle (known as a circadian rhythm) when daylight hours are short.
In addition to SAD, blue light can help with mood disorders, including premenstrual depression, anxiety, and some eating disorders. While blue light can potentially serve as one tool for treating certain types of mood disorders, it typically needs to be combined with other treatments, except in the case of seasonal affective disorder.
What are the risks of blue light?
Blue light can have positive effects on mental performance and mood. However, most of the benefits are associated with short-term exposure. Studies proving the benefits of blue light involve exposure of 30 minutes, and mood disorder treatments typically last 45 minutes or less.
Long-term exposure to blue light can have the opposite effect on people. Those who work on computers or in offices with LED lights may experience symptoms such as eye strain and an increased risk of developing long-term chronic conditions.
Here is a look at the potential risks of long-term blue light exposure.
Dry eyes
Blue light can cause dry eyes. However, this particular symptom is usually due to the fact that computer and device users stare at the screen for extended periods. Because they fail to blink, the user’s eyes can become dry.
Normally, people blink 15 times per minute, but studies have found that computer users only blink five to seven times. You can combat dry eyes by being conscious about blinking more often when on a computer or other digital device.
Eye strain
Blue light is also associated with eye strain. Short wavelength light decreases contrast, which causes people to have to strain to clearly see what is on the screen. So-called digital eye strain can cause headaches, dry eyes, fatigue, blurred vision, tearing, and difficulty focusing.
People who use computers for work can spend eight or more hours per day staring at screens, which can cause issues even if the user is conscious about blinking and activates features like dark mode to limit blue light.
Chronic conditions
Eye strain and dry eye issues can arise from computer use over the course of one day. Some conditions can come from long-term exposure to blue light.
Long-term exposure to blue light can damage cells in the retina, which is the part of the eye that is sensitive to light and sends information to the brain, which forms visual images. Retinal damage can lead to macular degeneration. This condition causes dark spots in your vision and can lead to a complete loss of sight.
Cell damage due to long-term blue-light exposure can also cause eye cancers, cataracts, and non-cancerous growths that affect vision.
Blue light and sleep
One of the most well-documented aspects of blue light is its effect on circadian rhythm. For this reason, blue light exposure during the daytime can serve as a treatment for insomnia.
Blue light exposure works by spurring the production of cortisol, a hormone that promotes alertness. At the same time, it blocks melatonin, which is the hormone that promotes sleep.
Though blue light exposure during the daytime can increase energy and promote concentration, getting too many short-wavelength rays at night can have a negative effect. The light can trick your body into producing cortisol, keeping you awake past the time when you normally fall asleep.
In severe instances, the effects of blue light could lead to sleep deprivation. A lack of sleep can harm your immune system, increase the risk of depression, and expose you to problems such as high blood pressure, heart disease, weight gain, diabetes, and certain cancers.
Combating the negative effects of blue light
In today’s digital world, you may find it impossible to limit exposure to blue light. Everyone uses devices to assist with normal daily tasks, from text messaging to navigating to an unfamiliar location using GPS-powered maps. Of course, many jobs also require extensive computer time.
While you may find it impossible to completely avoid blue light, you can take steps to limit exposure and combat many of the negative effects of extended exposure.
Avoid excessive screen use at night
Blue light affects the sleep cycle because it spurs hormone production. People who look at screens right before bedtime may experience insomnia. Studies found that heightened alertness came about after 30 minutes of blue light exposure. However, researchers also found that people who stopped blue light exposure three hours before bedtime had higher quality sleep than those who did not reduce exposure.
While turning off devices, computers, and television screens three hours before sleep can be beneficial, there are some alternatives — such as blue light blocking filters and glasses, which allow you to continue looking at screens while limiting the amount of blue light that reaches your eyes.
Install blue light filters
There are several options for blocking blue light from reaching your eyes. One of the more popular choices is a blue light filter, which you can affix to the front of a computer or device screen. These filters either reflect or absorb blue light to keep it from reaching the viewer’s eyes. Filters can offer additional benefits, such as helping to create a sharper picture.
Another option is to wear blue-light-blocking glasses. The advantage of this eyewear is that it blocks all blue light, including rays emitted from LED lights. If you have multiple screens at home, glasses will keep you from having to purchase filters for each of them.
Take regular breaks when using screens
You can develop good reading and digital viewing habits to avoid the negative impacts of blue light and issues like digital eye strain and dry eyes. For example, Mayo Clinic suggests employing the 20-20-20 method. This practice involves looking up every 20 minutes from your screen and gazing at a spot 20 feet or more away for at least 20 seconds. This amount of time gives your eyes the necessary break to avoid strain and dryness.
Schedule regular check-ups with an eye doctor
You can also schedule regular eye appointments to check for issues such as eye strain and more serious problems like macular degeneration. Optometrists can also help you find solutions to issues related to device use and blue light exposure.
People without glasses or existing conditions should visit an eye doctor every five years. However, those with concerns, including pain, blurred vision, or eye strain can make an appointment. Persistent symptoms could be a sign of a chronic condition that may worsen over time.
Regular eye checkups and common-sense eye care practices can help you avoid the negative impact of blue light even if you need to use computers and digital devices regularly during your day.