How to choose Myopic Lens

Choose Lenses mainly remember 4 points; material, shape, dispersion coefficient, refractive index.

Lens material mainly has glass (heavy fragile, wear-resistant, unsafe) , resin (light not fragile, impact-resistant, safe) , PC (lighter, non-fragile, impact-resistant, safe) .

Shape according to the region, divided into spherical and aspherical. For friends with low degrees, the difference between the two is not obvious. But if moderate to High Myopia, aspheric Lens is recommended. The dispersion Coefficient is usually expressed in Abelian numbers (usually between 30 and 58) . The larger the number, the smaller the dispersion, and the sharper the image. Common refractive indices are 1.56,160,167,1.74. The higher the refractive index, the thinner the Lens is at the same degree.