-
1.56 Semi Finished Progressive photo grey Optical Lenses
Lens refractive index is higher, the thinner lenses, the greater the density, hardness and better, on the contrary, the lower the refractive index, the thicker the lens, the smaller the density, hardness is also poor, general glass of high hardness, so the refractive index is generally at about 1.7, and resin film hardness is poorer, the refractive index is relatively low, resin piece on market at present is the most common refractive index of 1.499 or so, Slightly better is the ultra-thin version, which has a refractive index of around 1.56 and is also used the most.
