Different Material Types for Sunglass Lenses
There are multiple materials that are used to produce lenses for sunglasses. The best lens to use for a frame is often determined by price. However the function in addition to UV protection that you want from the lens makes certain lenses better than others for specific tasks.
It is worth noting that all these lenses can provide maximum (almost 100%) protection from UVA and UVB. So the more expensive or technically advanced the lens is, does not necessarily mean it is protecting the wearers eyes more.
PC lenses are strong and light. They have superior impact resistance and are less prone to cracking. They are low cost so are often used in fashion, sports and rimless sunglasses. Their strength and low price makes them incredibly versatile.
AC lenses are often used in fashion sunglasses, as they are low cost. They are very hard so offer good protection from scratching. They are however more brittle than PC, so are not suitable for use where pressure might be placed on the lenses. Over time they may crack if subjected to stress.
Nylon, or polyamide, is a performance material, it combines the advantages of polycarbonate and CR-39 lenses. Nylon lenses have an outstanding shock resistance while being extremely lightweight. Increasingly used in general purposes eyewear and for active sports.
CR-39 is thinner and weighs half as much as glass, and it is used widely for general purposes sunglasses. As it expands and contracts at a similar rate to Cellulose Acetate it is the prefered lens material for frames made with Acetate, as this avoids frames or lenses cracking.
Quality glass lenses offer the best viewing quality and are the most scratch-resistant. However, glass lenses are heavier, cost more money and are more prone to shattering on impact, so are not be the right choice for every situation.
Polarised lenses cut out the light from reflected surfaces. So when the sun shines on a flat surface like a lake, the glare produced by the reflection is removed. Perfect if you are doing water sports, fishing, skiiing, driving and more commonly just for general use.
TAC lenses are cut from a sheet of flat plastic, so there is a limit to how much this lens can be curved without affecting the wearers vision. TAC Polarised lenses are very light, which is great for the comfort of the wearer.
PC polarised lenses provide the same great polarised functionality, but in an injected lens that can be formed in whatever way required. So you are more able to use for wrapped styles. PC is also impact resistant. So PC Polarised lenses are great for sports or active uses.
Photochromic lenses darken and lighten depending on the brightness of the light/sun. The wearer then gets the optimium level of tint for the environment they are in. TAC lenses are very light, which is great for the comfort of the wearer. As with TAC Polarised there is a limit to how much this lens can be curved without affecting the wearers vision.
PC Photochromic lenses provide the same great photochromic functionality, but in an injected lens that can be formed in whaever way required. So you are more able to use for wrapped styles. PC is also impact resistant. So PC Photochromic lenses are great for sports or active uses.
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