The Eye Care Source website states that eyeglass lenses are available in three basic types of material: plastic, glass and polycarbonate. Each material has specific features and benefits. A person's vision correction and prescription and how the glasses will be used are factors to consider when choosing lens material.
Glass Lenses
Glass gives the clearest vision, protects eyes from ultraviolet light and is the most scratch-resistant of all the lens materials. However, glass is also the heaviest, cannot be used in some frame styles and can be dangerous because it breaks more easily than the other lens alternatives.
Plastic Lenses
Plastic is the most common material used for making eyeglass lenses and they are a good value for those who want a lightweight lens. Plastic is more shatter-resistant than glass, offers decent optical clarity and is easy to tint. The reason plastic is so popular is because the material meets several needs for a moderate price. Plastic lenses are not as good of a value for people with unusually strong prescriptions. The Opticianworks website states that the stronger an eyeglass prescription, the thicker the lenses. There are better cosmetic choices of lens material available for thick lenses.
Polycarbonate Lenses
Polycarbonate lenses are lighter than glass or plastic and are the most shatter-resistant lenses available. The Cleveland Clinic recommends polycarbonate lenses for people who regularly participate in sporting activities, work in a physical job environment and for children. Polycarbonate usually costs slightly more than glass or plastic but is a good value option for lens safety. The lenses do scratch easier so they need to be cleaned and handled carefully. Polycarbonate lenses can be lightly colored but do not tint dark enough to function as sunglass lenses.
Hi-Index and Aspheric Lenses
Hi-Index and aspheric lenses are an option for someone with really thick lenses. Hi-Index lenses are a plastic lens material that is compressed. This lens style is lighter and more comfortable to wear. Aspheric lenses are designed with different curves than a standard lens, making them thinner and flatter. This design difference creates a more usable portion of the lens for someone with a very strong prescription and makes the lenses more cosmetically attractive..
Other Specialty Lenses
A new generation of material is available for eyeglasses called Trivex. Similar to polycarbonate but with clearer optics, Trivex is still lightweight, shatter-resistant and thinner than plastic but not quite as thin as polycarbonate. The Trivex material has a higher quality of optics and provides clearer vision. The reviews of Trivex are positive. The July 2009 issue of "A to Z Materials" notes that optical professionals are reporting a high level of satisfaction from patients wearing Trivex lenses.
