What is blue light?
Blue light is the light with the shortest wavelength and highest energy in the spectrum of visible light. It has high energy and low wavelength which make it similar to ultraviolet rays.
Sources of blue light
The Sun is the greatest source of blue light, making it beneficial during the day. However, it is the man-made sources of blue light that concern us.
The screens of all our smartphones, flat-screen TVs, laptops and iPads emit a significant amount of blue light. It is said that blue light exposure is beneficial to us during the day. However, it is known that blue light affects our health negatively if we are exposed to it during the night.
Did you know the human cornea is not good at blocking blue light at all? This makes sure that a significant amount of blue light enters the eye, thereby making it easy to cause its effects. Let us see how blue light affects human health.
Benefits of blue light on human health
It is a known fact that blue light is required for staying alert and for improving mood and cognitive function. Exposure to blue light within the healthy limit and during the day improves your overall circadian rhythm.
Blue light is also used therapeutically. It is known to be effective in treating premalignant lesions of the skin and sun damage. It prevents skin cancer and is also known to be effective in treating acne. Some studies also show that being exposed to therapeutic blue light improves symptoms of depression.
Ill-effects of blue light
The anterior structures of the human eye, like the cornea, are not good at blocking blue light at all. Because of this, significant amounts of blue light reach the interior of the eye like the retina. The retina is the neuro-sensory layer of the eye which is responsible for receiving light and transmitting it to the brain via the optic nerve. Significant blue light exposure to the retina thereby causes dangerous outcomes to the eye as well as the brain.
1. Blue light exposure increases the risk of macular degeneration: Too much retinal exposure to blue light causes damage to the light-sensitive cells of the retina. This causes degeneration of the macula (the central part of the retina that is responsible for visual acuity). Macular degeneration eventually leads to vision loss.
2. Blue light causes digital eye strain: Lights with shorter wavelength and higher energy scatters the most. This causes blue light to be excellent at causing digital “noise” that contributes to eye strain. When we spend too much time in front of blue light-emitting screens, we experience symptoms of this eye strain – headaches, watering of our eyes, dry eyes etc.
3. Effects of blue light on our circadian rhythms: Exposure to light suppresses the release of a hormone called melatonin, which is the hormone that is responsible for maintaining our circadian rhythms. This is the reason we are told not to look at our smartphones before going to bed – blue light exposure makes it more difficult to fall asleep. Even dim light can interfere with our sleep and circadian rhythms. It not only makes it more difficult to fall asleep but it also significantly decreases the quality of our sleep. It is said that out of all the lights in the visible light spectrum, blue light affects our sleep cycle the most powerfully. Many studies show that a desynchronization of circadian rhythms is a risk factor for many tumor conditions, diabetes, obesity and even depression.
4. Blue light makes you age faster: Some reliable studies show that significant exposure to blue light decreases your longevity, accelerating your ageing process. Even if blue light does not directly reach your retina, it is a potentially damaging agent of brain cells.
5. Blue light and mental health: Some studies also show us that blue light exposure increases the levels of cortisol in our body. This was shown to cause an increased level of anxiety, depression and stress in the test subjects.
6. Blue light also negatively affects skin: It causes color changes, skin damage and inflammation of the skin. Blue light promotes stressors in the skin that are responsible for photo-aging. Photo-aging is the process of aging due to exposure to light.
Can blue light shorten your lifespan?
Since blue light is a relatively new concept, it is still very uncertain what the effects of blue light on the human life span are. Researches at Oregon State University tried to get an acceptable answer to this question by using an extremely common animal model – Drosophila or the fruit fly. Drosophila is a species that has been extensively used for many research studies because it has many physiological mechanisms that greatly resemble those of human beings.
This study showed that along with causing damage to the retina, blue light also causes extensive damage to our brain cells.
The fruit flies were exposed to blue LEDs for a minimum duration of twelve hours, followed by a period of twelve hours of darkness. This was done to mimic human exposure to electronics as closely as possible.
The flies that were thus exposed showed damage to their neurons and retinal cells. It was observed that their movement was disrupted and they were unable to perform their usual routine activities.
On further research, it was shown that there was an increased expression of stress-response genes in old flies but not in the young flies. The increase in this expression was directly proportional to the amount of blue light exposure. This finding was important in determining that blue light does act as a significant stressor in the aging process. This makes it highly likely that significant blue light exposure does shorten an individual’s lifespan.
Blue light exposure causes neuronal damage and other health ill effects even if it is not directly shining in your eyes. The same study proved this fact. Some fruit flies that were used in this experiment were mutant species that had not developed eyes. When these mutants were exposed to blue light, they too showed impaired development.
Since the long-term effects of blue light are not understood that well, it is relatively uncertain if significant exposure shortens a person’s lifespan. Although it is positively concluded that exposure to blue light decreases the longevity of Drosophila, the exact underlying mechanism of this is unknown.
Other pieces of evidence of how blue light may be shortening your lifespan
1. Along with controlling your circadian rhythm, blue light is important in inducing oxidative stress in your body, thereby affecting your ageing process significantly.
2. Ultraviolet light and radiation has been known to cause an acceleration of the aging process. It is a known mutagen that decreases an exposed individual’s longevity. Blue light has physical properties closest to ultraviolet light, therefore being a cause of concern.
3. Blue light is the most powerful out of the lights in the visible light spectrum. It not only enters the eye easily, but it also acts through the retina to affect neuronal circuits and systems negatively.
How can we save ourselves from the harmful effects of blue light?
Now that we are aware of the many hazards of blue light and the effect it has on our lifespan, let us see how we can prevent ourselves from falling victim to it.
1. Limit your screen time when you are not working.
2. Maintain adequate sleep hygiene and be sure not to expose yourselves to blue light before you go to bed.
3. Using sunscreen and sunglasses before going out on a sunny day.
4. If you have to use your devices at night, use a blue light filter app.
5. Get regular comprehensive eye exams.
6. Blue light blocking glasses – A high-quality pair of blue light blocking glasses act as a personal blue light filter that effectively blocks blue light from entering your eyes. Computer glasses also come under this category. They have characteristic yellow-tinted glasses that greatly limit the amount of blue light that reaches your eyes.
7. Apply a special screen filter in front of your devices – these screen filters are specially designed to limit the amount of blue light you are getting exposed to.
8. An easy method that is widely used to limit your time spent in front of blue-light emitting screens is the 20-20-20 rule. It is simple – for every 20 minutes spent in front of the screen, take a minimum of 20 seconds as a break spent looking at something that is at least 20 feet away. This technique has proved to be very effective in minimizing digital eye strain.
To conclude, the hazards of blue light exposure greatly overtake that of its benefits. As a generation of people who depend solely on our blue-light emitting devices for our work and play, it is important to understand the risks of unlimited blue light exposure. Reliable studies show that increased exposure to blue light accelerates the aging process, decreases longevity and reduces lifespan. This is a preventable issue, though, and it is important to limit the amount of time we spend in front of our laptops, TVs and smartphones.