Which sunglasses lenses are better?

Which sunglasses lenses are better? Reference to eyewear, many people' s understanding only limit to the material of eyewear and lenses.  

Metal alloys (metal eyewear), acetate (acetate eyewear) and pure titanium (titanium eyewear) which we talked about frequently are all within the scope of the eyewear material used. But regarding eyewear lenses material, non-professional people don’t know much about it. especially for name brands sunglasses lenses material, seldom people are familiar with it. Today, let’s have a rough learning of sunglasses lenses related knowledge.  Sunglasses Lenses

Sunglasses are usually used to shelter from the sunshine, in order to reduce the eyes’ fatigue or damage caused by the glare...