High energy visible light (HEV), also known as blue light, is emitted from the sun as well as from the screens of all our devices, including tablets, phones and laptops.
Of course, the fraction of exposure to blue light is much higher from the sun, but the advantage is that the sunlight is further away and not up close like the light from our devices.
The highest risk is posed from cell phones since people tend to use them throughout the day, by glaring at the screen for hours on end and scrolling repeatedly on social media.
Statistically, millennials are checking their phones 157 times a day, thus putting them at risk of contact with blue light that can possibly result in hyperpigmentation of the skin.
Protection for the skin through broad spectrum sunscreens does not always get rid of skin darkening completely and can still persist despite applying SPF 50 creams that stop 98 percent of UVB rays from affecting the skin.
These standard precautions sometimes do not work. One of the reasons suspected by dermatologists and photo-therapists is the increasing exposure to phone screens that emit the blue light. There is not enough data to back this rising concern.
But light filters are popular with manufacturers capitalising on the fear of blue light damaging sleeping patterns, eyesight and leading to obesity.
On the wide colour spectrum of sun rays, the harmful UVA and UVB rays are in the wavelength range of 280 nm and 400 nm. Similarly, blue light is characterised by the wavelength ranging between 380 nm and 500 nm. While the damaging blue light rays are in the range of 380 nm and 400 nm, the risk decreases at the higher end of the spectrum at 500 nm. Skin damage is manifested in colour changes, inflammation, skin ageing and damage on the skin surface.
Charité University of Medicine in Berlin, a renowned medical research centre in Europe, conducted a study to prove that carotenoids were destroyed by exposure to blue light and indirectly generated free radicals.
This was done with the help of administered doses of blue light irradiation. The destruction of carotenoids observed in the study was similar to the impact of infrared and ultraviolet rays on the skin.
The study observed seven females and two males aged between 26-63 years old, who were chosen based on the Fitzpatrick classification of skin, specifically type II and type III. Blue-violet light in the range of 380 to 495 nm from a digital phototherapy device was used in the experiment.
Two areas on the left and right forearm measuring 2 x 2 cm square were measured in the earmarked area five times in different places and a mean carotenoid concentration was calculated. The blue-violet irradiation was given in a 50 J/cm2 dose on one forearm and 100 J/cm2 on another forearm.
The light source was controlled by a power meter, which was placed at a certain distance for the light intensity to be precisely at 100 mW/cm2. The carotenoid concentration in the skin was checked immediately after 1 hour, 2 hours and 24 hours. To ensure the radicals were not formed from the heat of the light, the skin was cooled down.
One hour of sunbathing amounted to a dosage of 57 J/cm2 blue violet rays absorbed by the skin, similar to the parameters of the study. “The mean magnitude of the carotenoid destruction was determined to be 13.5 [percent] after irradiation at 50 J/cm2 and 21.2 [percent] after irradiation at 100 J/cm2. Depending on the irradiation dose, the restoration time was measured to be 1 hour for the dose of 50 J/cm2 and 24 hours for the dose of 100 J/cm2,” the results of the study said.
The study proved that irradiation with blue-violet lights generates free radicals in the skin by suppressing carotenoids, which lead to inflammation and skin diseases. However, this is just one of a few studies. More research still needs to be done, especially since blue-violet light is used to treat psoriasis, acne, neonatal jaundice and helps heal wounds, too.
Source: Medical Daily