Within the light spectrum that can be perceived by human eyes, blue light contains the highest amount of energy, which makes it the most likely visible light to cause damage to the eye. We are exposed to it on a daily basis from media devices but also from natural light, like the blue sky or the sun. We often don’t even realise we see it; whenever we look at the colour white, we actually see a mixture of differently colored light, including blue. Therefore, blue light is not a novel phenomenon of tech gadgets, but instead just a natural part of our surroundings.

Of course, just because something occurs naturally, it does not mean that it is harmless (read more about this in this article). Indeed there are studies that show that blue light can in principle damage the cells of the eye. In one of these studies, scientists exposed different cells of the eye in a petri dish to blue light and found that this damaged the cells and altered their interaction [3]. Moreover, they found that this could be intensified by adding a chemical called ‘retinol’ – a substance that the cells of the eye use to detect light. However, it is important to note that cells in a petri dish are generally more sensitive to light, since they are not in their native environment [4]. In another popular study, it was tested if mice wearing blue light blocking lenses would take less damage from a very bright light source than mice without those lenses [5]. This was indeed the case, however, lens-wearing mice still exhibited vision impairment, which suggests that also non-blue light can damage eyes. Moreover, the conditions of the experiment were rather extreme. The intensity of the used light was very high (around the intensity of a strong desk lamp at ca. 30cm distance), and the animals were exposed for up to one week. Taken together, such research convincingly shows that bright blue light can be dangerous in principle but does not show that electronic screens are dangerous.

Studies that were designed to investigate potential eye damage caused by screen-level blue light have so far not been able to report convincing evidence [6]. Moreover, the amount of blue light emitted by screens is more than ten times lower than a blue sky and, hence, most scientists and medical professionals agree that electronic screens are not harmful to their user’s eyes [7]. This was exemplified in 2017, when a UK company selling blue light blocking lenses was fined for “misleading advertisement” after claiming that blue light from screens and LEDs was responsible for retinal damage [8].