Selecting a Lens Material
Lenses can be made from glass, CR-39 plastic, polycarbonate, Trivex and some other specialty materials. There are ONLY TWO LENS MATERIALS APPROVED for use as sports lenses: polycarbonate and Trivex. SR-91 from Kaenon Polarized is also included on this list of unbreakable lenses because it is similar to Trivex. These are the two strongest lens materials in existence, but they are still not indestructible. If you are purchasing glasses for an activity that could lead to facial impact, you need unbreakable lenses.
Polycarbonate is the most popular lens for sports glasses. It is unbreakable, and is available as a tinted, Transitions, clear, or polarized lens.
Originally developed for military applications, Trivex is stronger, clearer, and lighter than polycarbonate. Trivex is available as a tinted, Transitions, or clear lens. To get a polarized Trivex, you need to order SR-91 lens material.
SR-91 is a polarized lens that is made from a material very similar to Trivex. Kaenon Polarized has the patent on this very impressive lens. We can put SR-91 prescription lenses in any Rx frame, whether it is from Kaenon or not.
Please read more about the various materials below. Every lens we offer is manufactured to improve vision. Our customers are never at risk of getting stuck with substandard lenses or coatings. If you have any questions, please contact us.
Trivex
Trivex has only been available to the public since 2003, and is still not offered by most manufacturers as a lens choice. We offer Trivex as an option in most prescription lenses, because it is quickly becoming the best thing that has ever happened to sports eyewear.
Most importantly for sports applications, Trivex minimizes distortion called “chromatic aberration”, which is distortion that occurs when objects are viewed away from the optical center. Trivex has a higher Abbe value than polycarbonate, so there is less Chromatic Abrasion (less peripheral color distortion) in a Trivex lens. Chromatic aberration is best measured by its “Abbe value”. In prescription eyewear, a higher Abbe value indicates less distortion as you look away from the center of the lens. Trivex has an Abbe value of about 45, while polycarbonate has an Abbe value of about 30.
Trivex naturally blocks 100% of the sun's harmful UV rays, similar to polycarbonate. It is also stronger and has higher scratch resistance than polycarbonate.
Trivex is usually about $25 to $40 more expensive than polycarbonate. If you are ordering prescription glasses and you don't see Trivex listed as an option, give us a call or send us an email to inquire about its availability. We are able to fit Trivex into more applications every day.
SR-91
SR-91 is a new polarized lens, and it is the perfect lens material for any sports eyewear. SR-91 polarization technology makes this lens exceptionally crisp and clear. The lens material is very similar to Trivex, and the polarization technology is very impressive. Kaenon Polarized, the sunglasses manufacturer, has the patent on SR-91. This lens material is featured in all of their sunglasses. All SR-91 lenses are polarized to eliminate glare, and they block 100% of UV rays and Blue Light.
When we first heard about the strength and clarity of SR-91, we were a little skeptical. So, at a recent eyewear trade show in New York, we borrowed an SR-91 lens blank and took it to a Drop Ball chamber used to test lenses for ANSI compliance. The normal 5/8-inch steel ball did nothing to the lens, so we put in a 4-inch solid steel ball bearing and dropped it 5 feet onto the lens. We wanted to see if the lens would shatter. Not only did the lens stay intact, there was not a single scratch on it. We have never seen a lens respond this well to a Drop Ball test. We are now big fans of the new SR-91 lens material.
SR-91 is the only polarized sports lens that is available in different degrees of darkness. The copper and grey SR-91 lenses are available with a 12%, 28%, or 50% light transmission. The Polarized Yellow lens is available in a 50% light transmission. NOTE: More than 90% of the polarized lenses we sell have a 12% Visible Light Transmission. Lenses with 25% or 50% VLT might not be dark enough for full-sun days. These are often worn by golfers who normally do not care for sunglasses at all, or fishermen at dusk or dawn.
The limitations of SR-91 include availability and price. The range of prescription blanks available is not as great as other materials that have been on the market for years. Currently, SR-91 prescription lenses are available from -3.00 to +5.00. As you would expect, this new, sharper lens material costs more than traditional lenses. Progressive SR-91 lenses are about 75% more expensive than polycarbonate. It takes about 2 weeks for us to process prescription SR-91 orders. Other lenses take 2-5 days. If sharp, glare-free vision is a priority, nothing is a better value than SR-91 lenses.
We can put SR-91 lenses in almost any frame you choose, regardless of who the manufacturer is. Call us for pricing if you do not see this option listed.
Polycarbonate
Polycarbonate is virtually unbreakable, and it is used exclusively by many of the world's finest sports glasses manufacturers. It is thinner, lighter, and stronger than glass. What's more, polycarbonate lenses can survive a 12-gauge shotgun blast from 10 yards away. (WARNING! If you try this at home, take the glasses off first.)
Polycarbonate naturally blocks almost all of the sun's harmful UV rays. No coatings are required to block UV rays on polycarbonate lenses, so don't let anyone sell you this option.
The strength of polycarbonate is partially derived from its flexibility. It will not shatter. This strength also contributes to its main weakness. Because polycarbonate is so flexible, it is also easily scratched. New lens coatings and hardeners have significantly improved polycarbonate's durability, but choosing a polycarbonate lens still requires an informed consumer. Quality lens treatments match the refractive index of the lens material and allow light to pass through the coating at the same speed as the lens. If light passes through the lens coating and the lens at two different speeds, your vision will be blurred.
Important note about scratched lenses:
If you scratch a polycarbonate or Trivex lens, you must choose one of two options. If you bought the glasses from us, send them back. We can usually replace the lens. If you can't replace the lens, THROW THEM AWAY! Polycarbonate and Trivex have amazing strength until they are scratched. Once they are damaged, they lose their ability to protect your eyes.
CR-39
CR-39 is the more frequently used lens material in prescription eyewear. It is the least expensive, and it works in environments that are isolated from sports related impact. For this reason, we hardly ever use it. This material is breakable, so it is not be a good choice in eyewear intended for active sport use. We can use CR-39 lenses in prescription inserts that are mounted behind a polycarbonate lens or goggle, or in glasses used for driving a car or lounging on a beach. If you are an active participant in any sporting event, you need a quality polycarbonate or Trivex lens in front of your eyes.
Evolution (Maui Jim)
Maui Jim Evolution is a higher index lens material that has great optics and results in a thinner lens. This is not unbreakable, so use care in selecting this material for active sports applications.
Glass
Glass lenses provide excellent scratch resistance and clarity. They are also about 40% heavier than polycarbonate or Trivex. Unfortunately, glass is not shatterproof.
If impact could be an issue, glass lenses are not the best choice. Serengeti makes impressive driving glasses with glass lenses, but none of our action sport glasses come with glass lenses.
