Types of Eyeglass Lenses

As technology advances, more and more types of lenses and coatings are being developed for the humble eyeglass. Gone are the days of simple concave glass, and even the revolutionary bifocal that Benjamin Franklin invented is now comparatively quaint. Of course both of those ideas are still in use, and indeed are the basis of any more advanced lens, but today there are a multitude of other options to upgrade your spectacles, from the virtually indestructible to the color-changing.

Polycarbonate Lenses

Polycarbonate is a material used in the glasses of children, those who lead active lifestyles, or those who are just accident-prone. These lenses are scratch-resistant and can really take a beating. They are most suitable for people who play sports, as they are durable and also offer some UV protection.

Trivex Lenses

Trivex lenses are very similar to polycarbonate lenses, but more like an updated version. They offer the scratch-resistance and durability of polycarbonate lenses, but are more lightweight and thin. They may also allow for a more precise prescription and thus better vision correction for some patients. However, they are more expensive than polycarbonate and may not be a better choice for children.

High Index Plastic Lenses

These are designed to accommodate people who require extra-strength prescriptions. Before the adoption of high index plastic, a heavy duty prescription meant heavy duty glasses. They were very thick glass, very heavy, and earned themselves the nickname “coke bottle” lenses. This new type allows for the same amount of correction in a smaller, more inconspicuous package that won’t weigh down the ears.

Photochromic Lenses

Photochromic lenses are possibly the most overtly futuristic type on this list. Using a special photosensitive coating enables this lens to “sense” UV rays and transition from a clear, normal lens into a darkened, sunglasses-type lens when the wearer is in the sun. This not only protects the wearer’s eyes from harmful UV rays effortlessly and at all times, but it also eliminates the need for prescription sunglasses which can be pricey but are often necessary when driving.

Polarized Sunglasses

Useful for sports, and driving primarily, polarized sunglasses reduce or eliminate unwanted glare. Because of the way these lenses negate the light that is reflected off of water or other flat surfaces, LCD screen displays may appear invisible to the wearer while these glasses are in use.

Aspheric Lenses

The majority of glasses lenses are at least partially spherical. These, however, are aspheric. Their surfaces are comprised of differing degrees of curvature. These tricky angles allow aspheric lenses to be thinner and flatter than nearly all other types, as well as offer the wearer a much larger “usable” portion of each lens within which vision is properly corrected.

Fog Free Lenses

A fog free lens is simply a coated plastic lens that encourages water to spread out evenly over the surface of the lens rather than to gather in tiny droplets and produce fog. The coating prevents water molecules from bonding with the lens, preferring instead to bond with each other and thus bead off the surface of the lens.