As you read on wikipedia, eyeglass lenses are available primarily in five materials; CR-39 (stands for Columbia Resin number 39), Hard Resin Plastics (usually high index polyurethanes), Polycarbonate, Trivex and Glass.
Most of the major online optical retailers offer CR-39, Polycarbonate and Hi-Index lenses. At least one, goggles4u.com, offers glass lenses (although there might others). I know of no online retailer that offers Trivex as a lens option (???). Zenni Optical appears to have a proprietary plastic compound with similar properties to CR-39, but with a higher index, as it's standard lens material. Even though there are several large, corporate lens manufacturers that usually supply your Brick and Mortar shops, there are quite a few other manufacturers that make their own lenses, usually in China and usually for a much lower price. Here in Europe, glass lenses are not uncommon. The major scare marketing push of Polycarbonate on to the US consumer has not had nearly the same result in most other parts of the world. As a result, fewer people are scared into only buying Polycarbonate if they might have a safety concern. It is understood that you have good reason to be concerned about keeping your better eye well protected, but personally, I don't think there are many cases of people losing their eyesight these days as a result of lens breakage. Trivex and some High Index compounds like Seiko's 1.67 MR-10 lenses have quite similar impact and strength properties to Polycarbonate, but with far superior optical properties. I would find a good local optician that has the time to listen to your concerns about safety but also knows enough about other materials to give you qualified advice. Arm yourself with some quality reference materials about Trivex, Seiko MR-10 and others and go speak to a professional. If they're unwilling to listen, go somewhere else - there are plenty of them around. Although most people on this forum have quite common corrective issues and are usually fine buying online, those of us with more atypical and severe conditions should at the very least become very knowledgeable about our conditions and available solutions. I'm not saying don't order online, but rather to be very well educated about all your available options and with a range of qualified advice before doing so. J. Evan On Jan 13, 5:25 am, gtbrooklyn <[email protected]> wrote: > I am pretty sure all online sellers offer all the different materials, > plastic, high-index and poly. Some of them will give you free lenses, > but it would most likely be plastic. Poly will most likely cost you > 19.99 and up. With your prescription you definitely need poly lenses. > > gtbrooklyn,www.savemoneyonglasses.com > On Jan 12, 1:36 pm, mandy <[email protected]> wrote: > > > > > I haven't gone through the archives completely (yet) so may be9 > > treading on a topic already covered. Wikipedia has a good article > > entitled "corrective lens". It seems polycarbonate is the most shatter- > > resistant of the available lens materials, with a number of other > > plastic types also very good. But how do we determine the material > > that is being used by online sellers? > > > The question is relevant to me because I have very limited vision in > > one eye and thus a special need to protect the other. But we all need > > to protect both eyes, thus the advice given me my an optometrist that > > I should have shatter-resistant lenses, specifically NOT glass, > > applies to us all. > > > So I ask you denizens of online eyeglasses: Have you figured out what > > materials online sellers are using for eyeglass lenses? > > > Many thanks.
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