There are two reasons to use sunglasses. The first factor is if you don’t like the bright sun shining in your eyes, as the dark surface area of the sunglasses helps to block out bright light and make the world appear darker. The second is that the sun’s ultraviolet rays can be hazardous in the long term, triggering all sorts of issues with your eyes including loss of vision and eye cancer. Excellent sunglasses secure versus this, as their lenses filter out the majority of the damaging UV rays.
So how do sunglasses work? The darkening effect is a really basic one: taking a look at the world through tinted lenses makes it seem darker to you– despite the fact that the impact is really simply a visual fallacy, it can help you if direct exposure to intense sunshine has the tendency to give you a headache or cause you to squint.
The UV-filtering effect, however, is more intricate. UV-filtering lenses are covered with unique chemicals that enable light to pass through them, however reflect away UV. UV rays are basically high-frequency light waves, which indicates that the chemical structure needs to be constructed to deflect higher frequency light while allowing through lower frequency light. This is tough science, and the materials had to do it are pricey.
The most complicated sunglasses of all are prescription sunglasses. These are sunglasses that not only secure from light and UV, but also work like normal glasses to remedy your eyesight. For this to work, it needs that typical vision-correction glasses are taken, tinted and coated with UV-reflecting chemicals– a complicated three-step procedure. However, all the ingredients work together perfectly, to produce sunglasses that are wearable by individuals who require their vision fixed all the time. It is even possible to purchase clear tinted lenses that fit over the top of your regular glasses, effectively a diy method of making prescription sunglasses.