The Pros and Cons of Blue Light

Opinions vary on the benefits and drawbacks of blue light. On one hand, it serves as an effective tool for combating winter blues and insomnia. On the other hand, blue light has the potential to cause irreversible damage to the human eye. How should we view blue light? What changes have occurred in the artificial light we experience every day? Understand why the human body requires light of this wavelength for biological effects? Additionally, when and how should we protect ourselves from the potential hazards of blue light? Read on to explore the pros and cons of blue light.

The Benefits of Light

Light not only helps us see things, but it is also a crucial factor in regulating our biological clocks and influencing our overall health. Light affects whether we are alert, focused, and productive, and whether we feel healthy and full of energy.

Scientific research has demonstrated that light possesses biological effects on our bodies. For instance, ultraviolet rays influence vitamin production. Exposure to bright light, particularly blue light, impacts our hormonal balance. Hormones within the body regulate an individual's sense of self and the sleep-wake cycle. During the day, the blue light component is relatively high, while it significantly diminishes in the evening.

When the external environment brightens, the body releases serotonin—one of the “happiness hormones”—and cortisol—a stress hormone. These two hormones keep us alert and energetic. However, melatonin is considered a sleep hormone; as night falls, it makes us feel tired and helps us drift off peacefully.

Light, especially blue light reaching the retina, also impacts our mental health. This is why light therapy has been successfully applied to treat seasonal affective disorder and insomnia. However, too much of anything can be harmful. Excessive exposure to light carries certain risks and can even cause damage.

The Drawbacks of Light

Excessive exposure to ultraviolet and blue-violet light may cause damage to the naked eye. Beyond potentially leading to uncomfortable conjunctival and corneal inflammation, it may also damage the eye's lens (such as cataracts) and particularly harm our retina (macular degeneration).

This is why wearing sunglasses with high UV protection is an essential protective measure in bright sunlight, especially in environments with intense glare, such as water surfaces or snowy slopes.

Light sources containing a significant amount of blue light in daily life

From light-emitting diodes (LEDs), xenon lamps, and energy-saving bulbs to the electromagnetic radiation emitted by screens, all these “new light sources” designed to make our lives better and more convenient contain more blue light than traditional light bulbs. This light, composed of different spectral components, means we are exposed to significantly higher levels of blue light than ever before. What adverse effects does this have on our vision?

Please remember that the amount of blue light your eyes are exposed to during one hour outdoors on a typical overcast day is 30 times greater than what you receive from sitting in front of a screen for one hour.

If we primarily wear glasses indoors, it makes sense that clear lenses don't need UV protection. However, you can also choose clear lenses with blue light filtering. Why?

Blue light emitted from light sources or screens may cause discomfort or fatigue in some individuals. Blue light filters can provide clearer visual images: different wavelengths of visible light refract slightly differently through the cornea and lens, meaning not all light converges at the same focal point on the retina. Some individuals may recognize these scenarios: viewing red from a distance or blue up close feels less straining; yet focusing on patterns with mixed red, green, and blue lines causes quicker fatigue than images composed of uniform or similar colors.

Additionally, for some individuals, light sources containing high levels of blue light can make it more difficult to fall asleep at night. When we are in a dark room or go out during dusk or nighttime, our eyes switch to a different visual mode; in low-light conditions, the human eye shifts from sensitivity to green light to sensitivity to high-energy blue light. This means we are exposed to a significant amount of blue light, thereby increasing our sensitivity to glare from bright lights. This scenario is familiar to drivers who experience temporary vision loss when blinded by oncoming headlights, especially those equipped with modern xenon or LED headlights. In such situations, blue light-blocking lenses provide a more comfortable visual experience.

Blue light filter lenses are transparent coatings applied to lenses that filter blue light. They reduce blue light within the 380–450 nm wavelength range. This means individuals seeking protection during indoor activities while retaining the benefits of blue light in the 450–500 nm range can enhance visual comfort through this technology!

How Electronic Devices Are Changing Our Vision

Tablets, smartphones, and other electronic displays have not only altered the spectrum of light we encounter but also transformed our visual behavior. Crucially, we must recognize that we now spend far more time viewing objects at close range than ever before, often due to excessively dim ambient lighting. Even children face this issue: “school-age myopia” refers to the growing number of children developing nearsightedness shortly after starting school.

If we don't spend enough time looking into the distance, our eyes lose the chance to properly relax. This can ultimately cause us to “lose” our ability to quickly shift focus between different distances, leading to digital eye strain. Additionally, when we stare at electronic screens, we naturally blink less frequently. This means the cornea receives less tear lubrication, causing our eyes to feel tired and sore. In the worst-case scenario, our vision could even be permanently damaged.

Our recommendation: We advise looking into the distance as frequently as possible to give your eyes a break, even when you're busy working on a laptop, tablet, or smartphone. At the same time, ensure your eyes are exposed to sufficient brightness and have adequate protection to avoid excessive UV and blue-violet light exposure.