Blue light is (somewhat ironically) all over our news feeds these days. It has become one of the latest health hot topics. But what exactly is blue light and what does it do?
Some articles say it causes eye strain, while others say it could result in blindness. Some products claim blue light is good for your concentration and some people claim it makes no impact on your body either way.
So what’s true and what’s pseudoscience? I’ve poured over as many studies and research papers as I can to find out what the scientific community has to say. Now, I’m ready to break down the results and help you separate fact from fiction.
What Is Blue Light & Where Does it Come From?
Blue light is a portion of the ultraviolet light spectrum.
UV light is technically a form of radiation. In small doses, ultraviolet radiation is safe, however, too much exposure can damage your skin and other tissues. The lens inside your eye helps absorb some UV, protecting the inside from damage. However, blue light is harder to absorb than other light frequencies. As a result, more blue light has the potential to penetrate the lens and damage the interior of the eye.
Like most ultraviolet light, the sun is its primary source. However, manmade and indoor devices also produce significant blue light. For example, smartphones, computers, tablets, and similar objects all create blue light. While they don’t emit as much as the sun, we spend so much time literally face-to-face with these devices, they are often considered to be more impactful on our health.
How Blue Light Affects Your Body
Blue light impacts hormone production in the brain, sometimes for the better, sometimes for the worse. The way blue light affects melatonin is an excellent example of a negative hormonal impact.
Melatonin is the hormone that makes you feel sleepy at night time. Exposure to blue light before bed tricks your brain into thinking it’s still day time, suppressing melatonin production and disrupting your circadian rhythm or “body clock.”
You can help maintain regular melatonin production by avoiding screens and digital devices for at least 30 minutes before bedtime.
Your tears contain something called a tear film, which prevents moisture from evaporating off the surface of your eye too quickly. Without a stable tear film, the tears don’t have enough time to moisturize and lubricate the eyes.
Studies show that blue light may affect the stability of the tear film, causing your eyes to feel irritated and tired.
Blue light can also cause dry eye in a more indirect way. Two studies have shown a link between sleep disorders and dry eye disease. The impact blue light has on your body’s ability to fall asleep and stay asleep can eventually lead to disordered sleeping, which may trigger dry eye.
Over time, the eye’s natural lens restructure, causing the lens to become increasingly cloudy. This development is called a cataract. Everyone develops cataracts eventually, in fact, most people over have some cataract development. However, some factors, like ultraviolet light, can speed up your cataract progression.
Concentration & Alertness
Blue light is a component of sunlight. And just like sunlight, some measure of blue light is good for you in the right circumstances.
Remember how blue light suppresses melatonin production? This is problematic at night time but can be very helpful during the day. In a study comparing the two, researchers found that blue light outperformed caffeine; providing heightened focus and alertness to test subjects. Interestingly, this effect seems to be even more pronounced in blue-eyed subjects.
The circadian rhythm affects more than just sleep patterns. Your body’s internal clock can impact your mental health, your cognitive skills, and even your weight.
Studies find that sleeping in front of the TV or laptop, or even just leaving too many lights on can disrupt the natural balance of your hormones. As a result, your blood sugar may increase, causing weight gain without taking in any extra calories.
Effects We’re Still Not Sure About
Digital Eye Strain
Blue light scatters more than other frequencies of light. As a result, it’s harder for the eye to focus. For years, we thought that blue light frequencies were the cause of digital eye strain for this exact reason.
However, recent studies indicate that blue light lenses offering 99% protection from blue light did not prevent digital eye strain symptoms, meaning the blue light was likely not the source of eye strain.
Some scientists still maintain that blue light is responsible for digital eye strain. But without a stronger consensus, it’s clear that more high-quality research will be necessary before we can tell whether blue light plays a role in eye strain or not.
Age-Related Macular Degeneration
Does blue light cause or contribute to age-related macular degeneration? That’s not an easy question to answer. There are several studies and publications which suggest that blue light can do significant damage to the retina. However, there is an equal measure of those who insist blue light has no impact on retinal health.
It would seem that it’s too early to determine how blue light relates to AMD. Having said that, I believe it’s better not to gamble with your eye health, so I recommend taking steps to protect your eyes from blue light and UV rays, in general, to be safe.
Mood & Mental Health
Researchers are only just starting to look into the impact blue light could have on mental health. There are some indicators that blue light could help treat premenstrual depression, bulimia, anxiety, and seasonal affective disorder.
If light is beneficial for people suffering from these disorders, it could be a major medical breakthrough. However, scientists have only scratched the surface of these topics, and more studies need to be done to really know whether this type of treatment is really possible or not.
Do Blue Light Lenses Actually Work?
Blue lenses are immensely popular right now. But do they actually work? Well, the short answer is yes and no.
Blue light lenses do filter out blue light, which helps protect your eyes from the potentially harmful effects. However, science indicates that blue light lenses may not prevent digital eye strain as much as we’d previously thought.
My opinion as an optometrist is that, until we have a better understanding of all the effects of blue light, it’s best to take as many precautions as possible, including investing in blue light lenses for computer, phone, and tablet use.
So Is Blue Light Good or Bad?
As frustrating as it is, medical science doesn’t always give us a definitive answer. Blue light is good for us in some ways, but bad for us in others. For the most part, it’s about moderation and timing. Taking steps to protect your eyes, and limiting your use of devices to daylight hours should keep you safe without completely eliminating your need for screens.