With the rapid advancement of technology, eyeglass lens is made of various materials. Some of the materials used in eyeglass lenses are traditional such as glasses and plastic; others are modern and newly invented. The eyeglass lenses introduced here include both of these materials and also involve some coating technologies.
A particular plastic material is used to form Hi-index eyeglass lens. This material refracts light in a special way. Eyeglass lenses of this kind are usually thinner than ordinary ones thus bring lightness. This kind of eyeglass lens helps people with high prescription out of thick and heavy lenses.
The special plastic used in polycarbonate eyeglass lens is more impact-resistant than standard plastic. This feature makes polycarbonate eyeglass lenses the good choice for active sports participants, those work in an environment which makes their eyeglasses easily scratched and mischievous children.
Aspheric eyeglass lens is designed with a flatter peripheral curvature than ordinary spherical eyeglass lens. These kind of lenses have much larger usable portion than standard lens by reducing the amount of bulging out. Aspheric eyeglass lenses are also much lighter and help reduce the image distortion greatly.
Photochromic eyeglass lens can automatically adjust to different light conditions. These eyeglass lenses have a special chemical coating that will be tinted darkened when exposed to sunlight and become clear indoors. They eliminate the need for a separate prescription sunglasses. Photochromic eyeglass lens can be made with either plastic or glass.
In addition to the above four popular eyeglass lens, there are lenses made of other materials including trivex lenses, anti-reflective coating lenses and polarized lenses.