You may want to go with an upgraded lens to improve the look, strength or functionality of your glasses.
“Regular plastic” eyeglass lenses refers to what is known in the industry as “CR-39 plastic” lenses.
Polycarbonate lenses are high index lenses that are known primarily for their exceptional impact resistance and anti-scratch coating. If you or your children are always bumping, scratching or dropping your eyeglasses, this is the material for you. Up to 10 times more impact resistant than standard plastic eyeglass lenses, polycarbonate is a first-rate option for people with an active lifestyle. Developed in the 1970s, polycarbonate has been protecting eyes for quite a while.
Developed in 2001, Trivex lenses are constructed from a newer plastic that shares many properties with polycarbonate. While also thin, scratch-resistant, highly impact-resistant and lightweight, Trivex lenses may be slightly thicker than polycarbonate lenses. For some vision prescriptions, they may provide a better visual clarity and more scratch resistance than polycarbonate lenses.
A high index lens is a lens that has a higher “index” of refraction. This means it has a greater ability to bend light rays to provide clear vision for people with stronger prescription glasses. But that’s the technical terminology. What do high index lenses mean for eyeglass wearers?
Thinner, lighter, and more visually appealing, that’s what! High index lenses are manufactured to be thinner at the edges of the lens and lighter in weight overall.
High index lenses are a good option for people who have strong prescriptions for myopia—commonly called “nearsightedness” due to a difficulty in focusing on far objects. A high-index lens can bend light rays more, while using less material in lenses created for both nearsighted and farsighted people (hyperopia).