The visible spectrum is made up of many types of light. Some of them are very harmful to our health while others do not pertain to any kind of danger. The visible spectrum lies from the wavelength of 400nm to 700nm. Discussing the spectrum is kind of a complex task, as researchers themselves have not been able to tell accurately where one kind of light ends or the other starts or vice versa. And just like every other thing that gets entrapped in rumors, the blue light topic is also a victim to people’s baseless theories. In this article, some of the common misconceptions about blue light will be cleared.
What exactly is Blue Light?
Blue light is a part of the visible spectrum and is said to lie between 500-318nm. That o course, is more of a hypothesis. There is a disagreement to the exact placing of lights within the spectrum as explained previously. Blue light has a very short wavelength & hence produces a large amount of energy. Research in ophthalmic studies suggests that long term exposure to the blue end of the spectrum can result in chronic damage to vision.
Some misconceptions about Blue light & Block lenses:
- All blue light is dangerous.
That isn’t true at all. A part of blue light is necessary for vision. Then which part of blue light is harmful? Based on current researches, the most harmful part of blue light is in between 455nm-415nm. Most of the retinal damage is done by the 40nm band and depending upon whose scale you are using, about 20% to 30% of blue light might cause harm in contradiction to the fact that blue light as a whole is harmful.
Newer blue block coatings function on the principle of reflecting away this 20% harmful blue light & letting the other remaining beneficial part to pass through like in anti blue light glasses.
- All kinds of blue lights are supposed to be blocked.
This is also a very big lie as only 20-30% part of blue light is harmful and must be blocked to protect eyesight damage. The latter is needed & is beneficial and the blue light blocking technology makes it possible to block this harmful part & letting the remainder pass through. This filtering of light is the main purpose of blocking lenses which come in two forms, light blue block tints & anti-reflective blue block coatings/ anti-blue light glasses.
- Blue block lenses must be deep yellow.
Not at all. Common theories led us to believe that only lenses tinted with an intense yellow will successfully filter out the light. But in reality, they just block out all the blue light – both good & bad. These traditional blue blockers blocked all of it without discrimination which led the scientists to get some data to zoom in on light & and calculate which light should be kept & which should be filtered out. These resulted in the newer lensesor anti-blue light glasses available these days, which do not need to be intense yellow. In fact, they can be lightly tinted with any color.