4 ms·
Glass lenses are only good for spherical prescriptions. If you have astigmatism, you need an aspherical lens, which cannot be shaped in glass.
by glitchc 4y ago
Glass lenses are only good for spherical prescriptions. If you have astigmatism, you need an aspherical lens, which cannot be shaped in glass.
- not_the_fda 4y agoThats not true, I have glass aspherical lens.
- glitchc 4y agoThat you wear for prescription glasses? Unlikely. Glass cannot be shaped into aspheres without very expensive grinding and polishing techniques. Multiple glass shapes are typically molded together to make an aspheric lens. The challenge is that molding the lens this way decreases the Abbe number significantly, which is why it’s not used for prescription eye glasses. If you have astigmatism, your lenses are most likely a polymer of some sort. Check with your optometrist.
- not_the_fda 4y agoI know exactly what I have. You can even get glass progressive lenses which are very aspherical. https://lensfactory.com/collections/progressive/products/progressive-premium-thin-glass-lenses-1-60 https://lensfactory.com/collections/progressive/products/pro...
- deleted 4y ago[deleted]
- fernirello 4y agoI've owned several pairs of aspherical lenses made of glass, ground by competent yet hardly exceptional shops. Only in the U.S. I found people uninterested in selling me glass lenses--exaggerated mimicry, "but they'll be so heavy!", etc.
- Fnoord 4y ago> "but they'll be so heavy!" Yeah, they are. If you only have say -2 its no big deal. I have -4 and with heavy glasses (I used to wear such) I get pain in top of my nose rather quickly.
- chongli 4y agoAnyone who is into photography knows this is flat-out untrue. Aspherical lenses are a big deal in the high-end camera lens world. Canon, Nikon, Leica, Zeiss, etc. all have aspherical lenses. I wear glasses and my glass lenses are made by Zeiss. My left eye has mild astigmatism and the glasses correct it perfectly. Each one is made from a single piece of glass that is ground to shape.