1. Choose frame material
At present, there are mostly metal, acetate, TR90 and PC frames in the market. You can choose the right frame according to your actual situation.
Metal frame
Normally the metal used for frames are nickel alloy, stainless steel, magal or titanium alloy. Let's sort by weight first: magal > stainless steel > nickel alloy > titanium alloy, sorted by cost: titanium alloy > magal > stainless steel > nickel alloy. High quality metal frame looks very When buying metal frames, the most thing needs to be worried about is plating color, many factories use very bad plating on metal, and the plating can't be lasting very long time, maybe around 1 month or even less than 1 month, the plating will peel off. Also, if you are allergic to metal, you are advised to choose other frames instead.
Acetate frame
The real acetate frame cost is higher than metal, but not that much. There is always metal wire inside acetate temple to make it adjustable after heating. The acetate itself can be generated with different patterns which is from inside to outside, so the whole acetate frame looks fancy than others. However, due to its high selling price, it's not popular to most people.
TR90 frame
TR90 (full name "Grilamid TR90") is a super light material. Such TR90 frame can reduce the burden of nose bridge and ear, make wearing more light and comfortable. Its impact-resistance and flexility make it suitable for sport sunglasses. Also, it can withstand high temperature of 350 degrees in a short time, not easy to melt and burn, so the frame is not easy to change shape and color and can wear longer.
PC frame
Low price of the PC material has a certain flexibility and impact resistance, rupturable but without debris cracking. Also, it can be painted in different colors or transfer with different patterns on the surface to make it always fresh in the market. However, the surface spray paint is not environmental protection, also it is easy to peel off for cheap painting. The frame can not adjust according to different face types. But due to its super-high cost-effective, currently PC frames is the best selling in the markets.
2. Choose lens material
At present, there are mostly AC, PC, glass, resin, nylon and TAC lenses in the market. You can choose the right lens according to your actual situation.
AC lens is the cheapest and very fragile, the cost is normally lower than 1USD/pc.
PC (PolyCarbonate) lens has strong impact resistance and is mostly used for sports glasses.
Glass lens has the best clarity, but it is much heavier and easy to break (tempered glass is the same).
Resin lens is strong, lightweight, high temperature resistance, strong uv resistance, but easy to get scratched.
Nylon lens is strong elasticity and strong impact resistance.
TAC lens is polarized lens itself and also can reach UV400 protection. It's made of seven thin sheets, the outermost two of which are super-hard wear layers. The second and sixth layers are shatterproof reinforcement layers; The third, the fifth layer is ultraviolet filter layer, the most intermediate layer is a polarizing filter layer. Polarizing lens can filter out reflected light and harmful ultraviolet ray effectively, also be the most popular sunglasses lens in the markets.
3. Choose the color
Match sunglasses according to your skin tone, face shape, what you're wearing, and occasions you wear it.
Generally speaking, gray, tan filter effect is good. Gray lenses can be evenly absorbed to any color spectrum, and the scenery seen after wearing the it will only darken without obvious color difference. Tawny lenses can filter out a lot of blue light, which can improve visual contrast and clarity, especially in the case of heavy air pollution or fog.
4. Choose the lens shades
A simple way to measure yourself is to put on sunglasses in front of a mirror, and you can see your pupils faintly. The light color lens has bad filter effect, while too dark lens can affect vision and impair color perception.
In short, the sunglasses you choose must prevent ultraviolet light, otherwise, although wearing sunglasses in the sun, it still can not avoid the the harmful light to eyes. The sunglasses will be just a "decoration".