Monocular lenses that are single focus optical lenses, is the most widely used optical lenses.

1.glass lenses have more resistance than other materials, the characteristics of scratch, but the relative weight of the sink, the refractive index is relatively high:

Ordinary film for the 1.523, ultra-thin film: 1.72 or more, up to 2.0.

2.polymer resin lenses

Polymer resin lenses are lighter than glass lenses, impact resistance is not easy to break, but because of its low hardness, so more likely than the glass scratches.

3.PC lens

There is also a material that is more resistant to polymer than the polymer, often used in aerial equipment, transparent windows, police masks, and astronauts on the helmet's mask, which is only about one-tenth of the weight of the glass, Resin lenses are only half the weight compared to the lens. General PC lenses need to add anti-scratch protective film, the use will be enough to get better time, most of the children's glasses used. PC lenses also have an important feature, that is, PC lenses have a detrimental UV effect, but its shortcomings also contains the surface easy to scratch