Ever stared at the computer screen for so long that your eyes started to feel different? What about the feeling you experience after you’ve spent half an hour or more looking at your mobile phone? What could be responsible for this eerie feeling that millions of people seem to recognize as a growing concern?
What is blue light and how does it affect the eyes and vision?
Every day, the eyes are exposed to blue light. The sun and the use of mobile devices are two examples of sources of this type of light, but do we truly understand what it is and how it affects our vision?
Although the idea that blue light is harmful to the retina is widely promoted, there is currently no scientific evidence to support it. However, it seems that the blue light from these devices disrupts circadian rhythms by inhibiting melatonin, making it more difficult to fall asleep.
There are also some scientific contradictions in this respect, which is why reasonable usage is critical, particularly in children and adolescents and adults who have difficulties falling asleep, and mobile device use should be limited before bedtime.
What is Blue Light?
Blue light is part of the visible light spectrum. Simply put, visible light is composed of numerous small fragments of colored light, with blue in the middle. Each ray in the visible spectrum has a distinct wavelength. For example, the ultraviolet wavelength is shorter than the infrared wavelength. Blue light is the section of the visible spectrum most similar to ultraviolet light.
Where does Blue Light come from?
Blue light is emitted by both natural and artificial sources. The sun is the primary natural source of blue light. When it comes to artificial sources, we can differentiate between:
- Led lights: Used in mobile phones and most other electronic devices. In recent years, the use of LED lighting has increased significantly. According to the most recent Mobile Report in Spain and worldwide, mobile phones are the most popular device among Spaniards, with 94.6% using them to access the Internet. On average, Spaniards spend two and a half hours in front of their smartphones each day. When we consider that these devices are used over short distances, the level of exposure to this type of light increases.
- Fluorescent tubes: Used to illuminate most office interiors and buildings in general. Although ophthalmologists document its effects on individuals with photosensitive epilepsy or light-related skin issues, we are so accustomed to them that we barely notice them.
Blue Light’s Effect on Vision
Depending on where they fall in the spectrum, blue light may be divided into two categories: blue-violet and blue-turquoise.
The least favorable impacts of blue-violet light include:
- Age-Associated Macular Degeneration (DMAE): An eye condition that affects the macula, which is the part of the retina responsible for detecting detail in our vision. This illness gradually damages the central vision, making it difficult to read and see small details. It commonly emerges around the age of 60; therefore, it is related to aging. When exposed to this type of light for an extended period, the cells in this area lose their ability to regenerate and may die. There is considerable debate over the impact of blue-violet light on the formation or degradation of DMAE. Studies will determine whether such an impact is potentially hazardous or not.
- Fatigue and visual stress: Emerges when the eyes spend an extended period of time in front of a smartphone or other device. It is also known as Visual Computer Syndrome (SVI). According to the US National Institute of Occupational Health and Safety, it affects one out of every seven persons and causes headaches, red, dry, and weary eyes, among other symptoms. Spending more than two hours each day in front of a computer or in multi-screen surroundings increases the chance of developing this illness.
- Alteration of circadian rhythms: According to Harvard Medical School neurologist Steven Lockley, blue light inhibits the production of melatonin, a sleep hormone. When we use mobile devices and other displays at night, we are telling our bodies that it is daylight, which means that it is not time to sleep. As a result, experts advise not using cellphones or electronics for at least two hours before bedtime. More empirical evidence on this topic may be found in Dr. Bowler’s study “Facebook use and sleep quality: Light interacts with socially induced alertness,” which was published in the British Journal of Psychology. According this author, using social networks late at night might create sleep disturbances that last till the next day.
On the other hand, the blue-turquoise light delivers several benefits. Some of them are:
- Pupillary constriction: This inherent defense mechanism that the retina possesses to shield the eyes from excessive light is carried out by blue-turquoise light.
- Anti jet lag: It is this kind of light that keeps the biological clock in sync. The blue-turquoise light is in charge of controlling sleep cycles, body temperature, and cognitive and memory functions when you stay up late or experience a sudden disruption in your routine, like going on a lengthy vacation.
- Visual acuity: The blue-turquoise light beams help the eye distinguish between different colors and other features of things, such as form, illumination, and distance.
- Decreased risk of cardiovascular disease: According to research, blue light exposure lowers blood pressure and lowers the risk of cardiovascular disease. Participants in the trial, which was published in the European Journal of Preventative Cardiology, were exposed to 30 minutes of whole-body blue light at a level equivalent to regular sunshine, or around 450 nanometers, before switching to a control light for another 30 minutes.
Various studies have found that blue light affects circadian cycles, producing sleep disorders, even though there is no scientific proof that it harms the retina. Because of this, it’s important to use mobile devices responsibly, especially for kids and teenagers, and to avoid using them just before bed.
In our next article, we will discuss a few possible solutions to this growing concern.
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