The surface radian of aspherical lens is different from that of ordinary spherical lens. In order to pursue the thinness of the lens, it needs to change the surface of the lens. Aspheric lens should be designed as flat as possible. However, the optical properties of flattened lenses, even if they are designed with aspheric surfaces, will decline rapidly. At the same time, the lens is lighter, thinner and flatter, and it still maintains excellent impact resistance, so that the wearer can use it safely.
1. Optical advantages: reduce the aberration of the lens and make the vision clearer.
2. Clear images can also be obtained at high luminosity: Although the spherical point focus lens is designed by the best base arc, the luminosity beyond + 7.00D-22.00D is not within the Cherning ellipse, and the aberration can not be eliminated. Only aspheric design can achieve better quality.
3. It can make the lens flatter, thinner and more beautiful. The higher the lenticity of spherical lens, the worse the appearance. Aspheric lens can be designed with flat base arc, which not only makes the appearance beautiful, but also reduces the peripheral magnification. Let others see the wearer's eyes, will not change a lot in size.
Defects of aspherical lenses:
1. Aspheric lens has a relatively small light area. When the eyeball rotates around, it will blur a little when looking at the outside through the lens edge, that is, the visual range of the line of sight becomes smaller.
2. Human's eyeball is spherical. The eyeball rotates to the edge. Through aspheric lens, the object near the eye appears protruding.