We hear a lot about blue light: it is one of the main causes of visual stress that affects those who spend many hours in front of a PC, mobile phone or tablet. That is practically everyone. “But blue light cannot be eliminated, it would be a mistake, because part of this radiation is fundamental for our health: it regulates the” sleep wake “rhythm, explains Franco Spedale, Ophthalmology Specialist and Director of the Ophthalmology Department Chiari Hospital, Brescia. In short, it is what our body warns that it is time to stay awake or to go to sleep, acting on a hormone essential for well-being, melatonin. In addition, it is essential for mood, attention and visual health. No wonder, light is essential for life, including humans. And while it is true that human sight has evolved with sunlight, which is the most intense natural source of blue light, it is equally true that today our exposure to this type of light has increased exponentially due to digital devices and LED lighting, which diffuse this type of radiation.
Characteristics of blue light
The light visible to the human eye is between 380 and 780 nanometers and the blue component is between 380 and 500 nanometers. It is an essential part of the spectrum, necessary to ensure adequate visual performance and the carrying out of certain physiological processes. On the other hand, however, blue light can potentially damage the eyes especially with shorter wavelength radiations (380-450 nanometers) within the spectrum which have a higher energy and therefore are more harmful to the eye tissue. .
And the data
Unlike UV rays, blue light reaches the retina and interacts with the macular pigment epithelium and photoreceptors, and here it can trigger cell damage. The damage can be serious and long-term, such as age-related macular degeneration or premature aging of the retina, or more immediate such as the sense of fatigue, dry eyes, the feeling of poor focus. “The blue light makes us alert, it raises our attention threshold, consequently the blink decreases by at least 5 times making the eyes drier”, the ophthalmologist goes on. “This is why after many hours spent on the computer it is possible to feel a sensation similar to that of having a foreign body in the eye: it is the poor lubrication of the eye”.
Smart protection
So if it is true that we do not have to eliminate blue light, we can certainly protect our eyes from the most harmful radiations, those with a shorter wavelength. “A foresight that everyone should have: those with vision problems should wear lenses capable of attenuating this part of blue light, but also those who have no visual defects but spend many hours at the computer or in front of screens should think they have some specific glasses, capable of optimally protecting the eyes ”, emphasizes Spedale. Technology comes to our rescue with lenses capable of absorbing harmful radiation, such as ZEISS BlueGuard lenses, thanks to two chemical compounds found within them – benzotriazole and benzophenone – capable of absorbing up to 40% of the blue spectrum. violet between 400 and 455 nanometers, however, allowing the beneficial wavelengths to pass. In addition, by blocking the blue light inside the material, they reduce residual reflections on the lens surface by up to 50% compared to traditional anti-blue light treatments.