Pull out the fog and scientifically prevent blue light
Anti-blue light glasses have always been a hot topic, the market is full of opinions, some see blue light as a flood beast, feel that all should be protected; some think that anti-blue light is iq tax is completely unnecessary.
So, what exactly is blue light? How should we look at anti-blue light?
Today we take you to deeply analyze blue light and scientifically understand anti-blue light.
What is blue light
Light is an integral part of the visual system. The wavelength of visible light in the human eye is between 380-780 nm. The blue light band (380 nm to 500 nm) is an important part of the spectrum, and it is closely related to human vision and physiology.
The formation of human vision is inseparable from sunlight, and sunlight is the strongest blue light source in nature. There are also many artificial blue light sources in modern life, such as LED lights (light-emitting diodes) and digital electronic screens.
Is blue light all harmful?
Blue light has two sides, both potentially harmful and has a positive impact on our health. Widely recognized by the scientific community, blue light is not only indispensable for vision, but it also plays an important role in improving alertness, mood and body clock.
Partial electromagnetic spectrum blue-violet spectrum (380-500 nm) can be divided into two parts, high-energy visible light (380-450 nm) and beneficial blue band (450-500 nm).
Potentially harmful blue light
High-energy visible light (HEV) in the blue-violet spectrum has been shown to be a major cause of photo-induced eye disease and chronic retinal damage such as age-related macular degeneration AMD. Blue light in this part of the band is potentially harmful to the human eye. Photons are able to interact with biological tissues at the molecular level due to their high energy, and the more energetic photons tend to increase the chance of eye health risks. It is worth mentioning that high-energy visible light can cause oxidative damage to the retina. Unlike ultraviolet radiation, blue light can reach and interact with retinal pigment epithelial cells and photoreceptor cells. High-energy blue light can trigger cell damage. Studies have shown that blue light is more damaging to the retina than light of other colors in the spectrum.
Digital electronic products such as computers, mobile phones, and tablets are becoming more popular, while the epidemic has accelerated the development trend of digitalization, and the use of various digital electronic devices has become an indispensable part of people's lives. Unconsciously, our eyes are increasingly exposed to the environment of various artificial blue light sources.
As shown in the figure above, the spectrum of incandescent lamps, modern white LEDs and solar emission is between 380-500nm, and the dotted line is the display spectrum of a typical smartphone. This graph shows that the blue light emitted by LEDs and digital product displays has a higher intensity than traditional light sources.
Digital eye strain
I believe that many people have experienced digital eye fatigue due to excessive use of electronic screens.
Digital eye strain, formerly known as computer vision syndrome (CVS), includes excessive use of the eyes, vision-related symptoms, and amblyopia problems, which are all related to the heavy use of computer and digital product displays, high-intensity reading, and prolonged close-up use of the eyes.
When the need for the eye exceeds the eye's ability to adjust itself to maintain clear and comfortable vision, it can lead to an overload of our visual system – an overload that ultimately causes visual fatigue.
Digital eye strain, including glare, blurred vision, pain in or around the eyes, dryness and eye strain, is associated with extensive use of digital product displays, high-intensity reading, and prolonged close-range eye use.
Blue light and digital eye strain
Blue light has a certain relationship with digital eye fatigue and may produce symptoms such as blurred vision and visual discomfort. When short-wave blue light passes through the medium of the human eye, it can induce luminous physical effects, causing two negative effects - light scattering and longitudinal chromatic aberration. The first negative effect is light scattering. This effect leads to an increase in "visual noise" in the retina, which leads to dizziness, decreased visual contrast, and ultimately digital eye strain.
Schematic of the scattering of blue light in the human eye
The second negative effect is longitudinal chromatic aberration, which can make the visual image perhaps look blurry or have noticeable color edges.
Different focal points of blue, green, and red light (FB, FG, and FR). The focus of blue light is located at 1.5 diopters in front of the fovea of the retina, rather than focusing on the fovea with the clearest vision, thus creating aberrations.
Beneficial blue light
Blue light also contains beneficial blue light, which can trigger the normal physiological processes of the human body and plays an important role in controlling the biological clock and maintaining physical and mental health.
Rod cells and cone cells are photoreceptor cells that produce vision in both bright (day) light and dark (night) light conditions. Another class of photoreceptor cells, namely intrinsic photoreceptor retinal ganglion cells (ipRGCs), do not have an effect on vision, but can feel the intensity of light, drive pupillary aperture control and other physiological and psychological mechanisms. Retinal ganglion cells play a key role in circadian rhythms, and it contributes to our health and sleep cycles.
Irradiation of blue light on the retina regulates melatonin secretion and thus affects the waking cycle. Among them, the blue light in the 464nm-490nm band has the most obvious inhibitory effect on melatonin secretion.
Studies have shown that blue light also has an important positive effect on children's eye development.
Scientific blue light prevention
Correct understanding of blue light and the impact of blue light on eye health can correctly choose anti-blue light glasses. Whether blue light in electronic digital products and artificial light sources is harmful to the human eye depends on a number of factors such as the band, intensity and time of contact. If you live outdoors for daily work, it is more appropriate to wear non-anti-blue light lenses; if you often look at electronic screens at high intensity for a long time, it is recommended to wear anti-blue light lenses.
When choosing anti-blue light lenses, it should also be noted that if the short-wave high-energy blue light that the lens cannot block cannot be blocked, it will not have the effect of blue light protection; and the barrier rate is too high, shielding the blue light of the beneficial spectrum, which may cause excessive protection. Anti-blue light lenses with poor light transmittance and obvious yellowing of color may also cause distortion and clarity of the eyes' vision, which can cause eye fatigue. Therefore, lens anti-blue light is not the more shielding the better, light transmittance and protection must be taken into account.
Blue light has potential risks but also benefits, the essential purpose of glasses is to see clearly optimistic, the ideal anti-blue light lens should achieve a scientific balance between blocking potentially harmful blue light and retaining beneficial blue light.
In this way, we can enjoy the beneficial blue light to promote the health of the body, but also to protect the blue light damage to the eyes, alleviate the visual fatigue caused by the use of digital products.
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