Why are the lenses of our Prisma Blue Blocking Glasses so heavily tinted?
Why should you accept a yellow tint when there are completely transparent glasses that promise blue light protection? In fact, this is an empty promise that many manufacturers make. A short excursion into physics quickly makes this clear.
When blue light is removed, the world becomes yellow!
Answer from world renown light scientist, Dr. med. Alexander Wunsch
In my opinion, what most eyewear professionals can offer when it comes to blue light protection is in no way sufficient! I have often experienced how opticians are amazed when they demonstrate with a spectrometer the low level of blue light protection that the lenses of well-known manufacturers offer...
A rule of thumb applies due to the physical laws of optics: if a lens doesn't look yellow, it can hardly filter blue light. However, the following also applies: not every yellow glass filters out enough blue light, especially not the parts that are particularly harmful to the eyes and retina...
A colour filter separates the incident light into two parts: one part is transmitted and a second part is removed from the full spectrum. This division of the spectrum can be achieved using various techniques, such as reflection or absorption. PRiSMA works with a combination of both technologies to achieve optimal filter effect.
According to the laws of optics, an absorption filter that removes blue light from the spectrum looks yellow. Similarly, a filter that eliminates the yellow component would look blue. According to the principle of additive colour mixing, which applies to the mixing of coloured light, the colours red, green and blue together produce white light. If you now remove the blue component, what remains is red and green light, which together create the perception of yellow.
For this reason, effective blue light filters always look yellow. This means that the consumer can judge at any time, even without measuring devices, whether a filter really has the promised filter effect, because a pale yellow filter allows much more blue components to pass through than the blue filter in a strong yellow or a saturated orange lens.