Why do polycarbonate lenses crack?

Polycarbonate lenses can be progressive lenses, which feature multiple zones of vision correction. Polycarbonate lenses tend to be recommended for children, because they’re lightweight, safe, and impact resistant if a child drops them or does some roughhousing making use of their friends. Trivex might help provide additional protection and durability due to the lens design and excellent impact resistance. In the United States, most high index lenses are made from the various plastic materials.
Sometimes they’re too small for the glasses to fit into properly; sometimes they snap shut with the force of an alligator’s bite. Usually the frames bear the brunt of it, but damage to the lenses wouldn’t be unthinkable. My next pair were also Lenscrafters and never had the cracking problem; however they are thick plastic frames. Your lenses most likely have experienced lens “crazing”, a common problem especially through the summer.

• It’s important to notice that impact resistant does not mean shatterproof.
• Stripping solutions can be found in some eye care practitioners and optical laboratories for this purpose; however, the results will change depending on the type of lens and coating used.
• Also, keep your glasses from extremely hot or cold temperatures.
• They are able to still break, therefore official safety glasses ought to be worn for eye-hazardous jobs and sports.

Maybe you have seen the zyl rectangular frame where in fact the lenses are in there so tightly that the very best center of the lens now protrudes from front of the bevel of the frame? Maybe you have wondered what may be the result of looking thru the lenses which were crammed into this frame? To explore this further we have to go back to the fundamentals of base curve theory. Remember, here we have been addressing that the front base curve minus the back base curve equals the overall prescription. Also, we have to understand that creating great vision depends on lens curves being consistent.

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However, Trivex lenses are usually nearly as thin as polycarbonate lenses, plus they cost more. While Trivex lenses are naturally scratch-resistant, you range from AR coatings for additional scratch resistance or blue-light protection. Originally developed by the military for helicopter windshields and fighter jet canopies, Trivex was eventually tailored for used in optical lenses. Trivex lenses are lightweight and exceptionally clear which lends itself to incredible comfort. The material can be stable, therefore the lens won’t change to look at as time passes as other materials might do.

Polycarbonate lenses are soft and flexible, that is why is them incredibly impact-resistant. Flexible spending accounts , health savings accounts , and out-of-network vision insurance coverage can all be used towards awesome new prescription sunglasses, eyeglasses, and goggles. If you notice a web of hairline cracks on your glasses, call your eye doctor or the optical shop where you purchased them to find a remedy that can restore your vision. A one- or two-year manufacturer’s guarantee is standard on most prescription eyeglasses.

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My guess is that you have AR coating on the lenses and that the coating is cracking, not the lens itself. The AR coating can be cracked because it is less flexible than the polycarbonate lens.
Various other countries still work with a lot of glass material for high index lenses. Glass comes in very high indices such as for example 1.8 and 1.9 but because of its density it is still very heavy. Glass lenses also take longer for optical labs to fabricate. High index plastic lenses can be used in desired rimless and 3 piece mount frames. Your brand-new prescriptive eyeglasses lenses suddenly have weird looking scratches. Yet you know for sure that the lenses did not get scratched and you also cannot clean them off.
This means that your warranty might not cover crazing that was caused by, for example, leaving glasses in a hot car. Remember that some retailers may charge you a warranty fee to repair or replace your crazed lenses.

Factors to consider when selecting a frame include facial features, age, activities and the prescription itself. Ordinarily a strong prescription requires thicker lenses, which can affect the selection of frames.

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Some warranties cover crazing produced by a manufacturing flaw, which often appears during the first six months of regular use. Use a lens spray manufactured exclusively for cleaning eyeglasses or lotion-free dish soap and a clean, lint-free cotton towel to clean your spectacles properly.
Exactly like frames, there’s plenty of different types of lens that are used in eyewear. Since theemergence of eyewear in the 13th Century, glass will be blown into shape to magnify objects and would be used in early forms of glasses. Early glasses were tricky to find and usually only afforded by the absolute wealthiest people, not to mention the refractive power of the early lenses were pretty limited. On the centuries, glass became less expensive and accessible, thanks to huge improvements in understanding optics, refractive measurements, and glass manufacturing processes. You can add a variety of different coatings and treatments to polycarbonate lenses, including anti-reflective coatings and blue-light-filtering coatings.