What are sunglasses made of?
Basically, sunglasses are made of two components: lenses and frames. Frames can be nothing more than thin metal wires that surround the lenses, or they can be large plastic casings, especially in sport sunglasses and oversized sunglasses. Most frames are flat so that they can be folded and put into a pocket. Many designer sunglasses come with soft pouches or cases for protection. Lenses come in almost every color of the spectrum. Polycarbonate lenses are especially valuable when working in hazardous environments or when made for sport sunglasses, as they are nearly indestructible.
How do polarized lenses work?
Generally, light reflected from surfaces such as a flat road or smooth water is horizontally polarized. This means that, instead of light being scattered in all directions in more usual ways, reflected light generally travels in a more horizontally oriented direction. This creates an annoying and sometimes dangerous intensity of light that we experience as glare.
Polarized lenses contain a special filter that blocks this type of intense reflected light, reducing glare, so your eyes are more comfortable and you can see better.
In addition, polarized lenses may reduce the visibility of images produced by liquid crystal displays (LCDs) found on the dashboards of some cars or in other places such as the digital screens on automatic teller (bank) machines.
So for most outdoor sports and activities, polarized sunglasses offer great advantages.
Are mirrored lenses better for sunglasses?
It depends on your attitude. If you want to hide your eyes, mirrored lenses are definitely the way to go. As for glare reduction or UV protection, this eyewear is no different from discount sunglasses with colored lenses.
What about gradient lenses?
The gradient lens is darker on the top of the lens for added protection and transparent at the bottom. If your activities vary and you need clear vision mixed with your eye protection, the gradient sunglass can be a useful alternative. Polarized sunglasses are especially useful for sports and outdoor activities, as they reduce the sun's glare; men's sunglasses are often polarized.
Should I buy prescription sunglasses?
Prescription lenses are very common and generally cost a little more than other corrective eyeglasses. Prescription sunglasses are great for those who want to participate in outdoor sports but don't want to wear contacts, as contacts often cause eye dry and fatigue.
What are photochromic lenses?
Photochromic lenses darken upon exposure to bright light, and will gradually return to their clear state when light fades. These sunglasses have been around for decades and are very popular.