Best Lens Materials For Sunglasses
Sunglasses & Optical Lenses: What you need to know
Clarity is probably the biggest issue. If your vision isn’t clear, what’s the point? It used to be that glass offered the best clarity– still does. So newer developments were made that increased clarity and durability, while decreasing the weight.
Lightweight plastic lenses were a ‘second generation’ product and are still used greatly today. But further advances have been made, making Polycarbonate lenses lighter and better able to handle more impact— a great choice for children and sports eyewear. Still, another newer progression is Trivex, an engineered product that has a higher ability to contain light dispersion, which prevents impediments like halos around objects. And finally, high-index plastic lenses are thinner and refract light better. So what’s behind all of these choices?
Science. Considerations include refraction index, Abbe value, aspheric design, thickness and lens coatings. Sounds like Greek? Maybe, but it’s worth understanding if you are to make an informed purchase.
Refraction: How efficiently light travels through a lens. A high refraction index means less material is needed to bend light, making it thinner, and therefore preferable
Abbe value: Measures how widely light wavelengths are dispersed. A high Abbe value eliminates halos and light ‘cloudiness’, which is therefore preferable
Lens thickness: Polycarbonate and Trivex lenses can be made much thinner than other options. Thinner lenses mean less weight.
Aspheric design: This refers to the curvature of the lens. When the lens gradually changes, a thinner, flatter material can be used without changing clarity or performance, thus making it preferable.
Coatings: Things like anti-scratch, anti-reflective and UV-blocking coatings can all help maintain the wear of your glasses and the performance, therefore making it more preferable.
It seems that buying sunglasses is all about the frame. Metal or plastic. Round or Aviator. But what’s often overlooked are the lenses—the generally invisible component that actually lets you see. But it really should be a consideration, because after the purchase, lenses are what makes you see clearly—or not. Are durable—or not. Are safe—or not.
You may not feel that you have that much selection when you find a pair of glasses that look good on you. The item may only be offered with one, maybe two options, if prescription. So why is this all important? Well, the more you know, the easier and better your shopping experience will be. So here’s what to look for in glasses.
