The refractive index of a lens is determined by the material used in the discount prescription glasses lens. When the central thickness is the same, lenses of the same degree and material have a higher refractive index and thinner edges.

When the brand is the same, the high or low refractive index indicates the difference in the materials used, and it can also determine the price of the lens. The higher the refractive index, the higher the price, and vice versa.

The reason for mentioning the wear resistance coefficient is that resin lenses are not very wear-resistant when they first enter the eyeglass mart, and wear they for half a year before the lenses are worn out. But with the continuous iteration and updating of technology, the surface hardness of ordinary resin lenses has been improved after hardening treatment, and then combined with surface plating and hard film to solve the problem of non wear resistance of lenses.

Although the hardness cannot be compared with glass sheets, most of the glass sheets have been withdrawn from the market, and the remaining ones mainly focus on high refractive index. By the way, let's talk about PC chips. Lightweight, high toughness, and less prone to breakage are significant advantages of PC chips.

By the way, let me teach you a little trick. To identify the hardness of lenses, you can use objects of the same material to draw circles on the sample. Based on the depth and thickness of the scratches, you can roughly detect the surface hardness of the lenses. Of course, this requires the glasses best place to buy eyeglasses to provide props and samples for such testing.