A lens with a convex or concave shape cut from a sphere is called a spherical lens. Due to the inevitable occurrence of aberrations in spherical eyeglass online lenses, there have been lenses that correct the shortcomings of spherical lenses, namely nonspherical lenses.

Nonspherical lenses refer to rotating surfaces (such as parabolas) with the same non-circular cross-section on all meridians. Its biggest advantage is that there is no distortion of objects in the edge field of view, with less visual distortion and a more realistic visual experience. At the same time, the edges of the lens are thinner than ordinary spherical lenses.

The eyeglass online lenses are coated to meet the needs of different usage scenarios. If there are no specific requirements, they will also be coated with a hard film to increase hardness. Films such as green, yellow, green, blue, and purple are added to the hard film with other functional film layers.

Green film is the most common film layer, mostly used for anti-reflection function. Purple film has anti anti-glare function and is commonly found in driving eyeglass online lenses. The function of blue film is intermediate between green film and purple film, with balanced performance, but with relatively high technical requirements.

The yellow-green film is made less, but it looks very nice. The color of the film layer is changed by changing the thickness of the coated layer. The lighter the reflection of the film layer color, the better the quality can be determined.

The greater the reflection, the higher the light transmittance, which can achieve higher light transmittance. Super water film is one of the functional film layers, which means that the waterproof and anti-fouling properties of the lens are better, and this type of film layer is smoother.