Aspheric designs are available in single vision lenses for the correction of nearsightedness, farsightedness and astigmatism, and in progressive lenses, bifocals and trifocals for presbyopia. Although most aspheric lenses are made from high-index materials, they are available in regular plastic, too.
High-Index and Polycarbonate lenses High-index eyeglass lenses are the right choice if you want thinner, lighter lenses and eyeglasses that are as attractive and comfortable as possible. Thinner, lighter high-index lenses are especially recommended if you have a strong eyeglass prescription for nearsightedness, farsightedness or astigmatism.
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Tinted Lenses vs. Polarized Lenses While tinted sunglasses are great for reducing brightness, think about reading your favorite book outside on a hammock, they don’t necessarily eliminate harsh glares like polarized sunglasses. Don’t let darker lenses fool you into thinking they offer more protection from UV rays, as the darkness of lenses does not accurately represent the lenses’ ability to block UV rays.
What Are Multifocal Eyeglass Lenses? If you are in your mid 40’s or older you probably have glasses with multifocal lenses, like bifocals or trifocals. These have two or more prescriptions to correct your vision. In the past, you could spot this type of lens by the line between the two sections. But today’s products often look seamless. Bifocals.
Trivex lenses, however, are composed of a urethane-based monomer and are made from a cast molding process similar to how regular plastic lenses are made. This gives Trivex lenses the advantage of crisper optics than injection-molded polycarbonate lenses, according to PPG.