1. Anti-reflective protective lens: This kind of lens is coated with a thin layer of magnesium fluoride to prevent strong light reflection, so that you can see things more clearly and not interfere with strong light. To check if your sunglasses are really anti-reflective lenses, align the glasses with the light source. If you see a purple or green reflection, it means that there is indeed an anti-reflective protective film on the lens.
2. Colored lenses: Also known as "stained lenses", in the process of making lenses, adding some chemicals to make the lenses appear color to absorb light of a specific wavelength. This is the type of lens most commonly used in sunglasses.
3. Coloring lens: This lens presents the same effect as a colored lens. It is only made in a different way. It is applied to the surface of the lens. The most well-known is the "gradual color coating lens". The color is The deepest above, then fade down. Generally, sunglasses with degrees are mostly processed by coloring.
4. Polarized lenses: In order to filter the glare of the sun in the equal direction on the surface of the water, land or snow, a vertical special coating is added to the lens, which is called a polarized lens. Ideal for outdoor sports such as sea activities, skiing or fishing.
5. Color-changing lenses: Some people also call them "photosensitive lenses." Because the silver halide chemical is added to the lens, the original transparent and colorless lens will become a colored lens when it is exposed to strong light, so it is suitable for indoor and outdoor use.