Sunglasses

• If they are for fishing or use on water, polarization is a must; polarized glasses provide more sun protection.

If you want your sunglasses to protect you from these risks, look for pairs that block at least 99% of UVB rays and at least 95% of UVA rays
Look for scratch resistance
Use the shape of your face to help you pick your sunglasses shape.
Oval face: The oval type usually has the "perfect face shape", and can wear any style of glasses. Avoid frames that are either too thick or too thin. Don't choose frames wider than your face width
Square face: Because this face shape has very straight, pronounced jawline and edges, choose round glasses to balance out these features.
The weight should be evenly distributed between your ears and nose, and your eyelashes shouldn't touch the frame or lenses. 
In addition, use the measuring rule that an "eyelash is less than the lens".
Check for distortion. Hold the lenses up to a fluorescent lamp. As you move the sunglasses up and down, check that wave distortion doesn't happen
The best choice is glass or resin material.
http://www.wikihow.com/Pick-Sunglasses

• NXT Polyurethane

    This lens material truly is the top of the line. Combining all the benefits of optical glass with all of polycarbonates performance capabilities making NXT Polyurethane lenses the best choice for anyone willing to shell out the cash to get them. NXT lenses are made with Trivex, an advanced polymer material whose advantages include extreme impact resistance, superior optical clarity and ultralight weight
https://www.evo.com/guides/how-to-buy-sunglasses