There's absolutely nothing unsafe about glass lenses if you're a normal person and don't abuse them. They're actually superior to plastic in terms of longevity and durability. What I've found is that the tradeoff is durability vs. weight. Glass is heavier than plastic but if your glasses are well-fitted and adjusted, this is not a problem. Also, in terms of cleaning you can be a lot less careful with glass and they won't scratch. I had a pair of glasses with plastic lenses and my wife tried to "help" me by cleaning them with a paper towel when I wasn't around. The lenses got scratched up and unusable. Never again...it's glass lenses in Shuron frames for me!

I would rephrase that as: There's nothing dangerous about them until an accident happens. And that's why it's not worth it to me. I saw my dad's eye surgery from a glass-lenses incident years ago - he was lucky, it still was an awful experience. Should he have been wearing a pair of goggles while working in the yard? Sure. But I've forgotten that too!

Most eye 'glasses' are eye plastics. Plastic lenses are softer than cellulose = kleenex scratches them. There is no easy way to avoid scratching plastic apart from detergent rinsing and soft lens cloth pat drying. I buy true glass lenses, hardened so they break into splinters (I have never broken one) To clean, I wash with warm water and dish soap = they last for years and I need new ones due to eye aging before they ever get scratchy. A few others made this point as well.

I have glass lenses, but I don't care to find out what happens if ever an airbag explodes into my face.

Fun fact: if you're ever institutionalized for suicide watch, they confiscate your spectacles due to a perceived risk of being able to break them and cut yourself, even if your spectacles aren't made of glass.

Glass lenses are only good for spherical prescriptions. If you have astigmatism, you need an aspherical lens, which cannot be shaped in glass.

Anyone 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.

Thats not true, I have glass aspherical lens.

That 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.

I know exactly what I have. You can even get glass progressive lenses which are very aspherical. https://lensfactory.com/collections/progressive/products/pro...

I'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.

> "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.