Different people, how to choose 1.71 lenses,1.71 lenses since its inception, to fill the gap in the lens market price performance, to find the balance point between the lens refractive index and the price (1.60, 1.67 cheap, but thick; 1.74 thin, but very expensive), thin lenses, cost-effective, plus Abbe number effectively control dispersion, so it is popular in the market. However, the 1.71 lens has various functions such as daily general use, anti-blue light, PMC super bright, intelligent color change, progressive multi-focus, multi-effect protection, etc.