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Comment by booleandilemma | Hacker News Reader

Why does the camera lens not shatter in this case?

And in the same vein, what happens to peoples’ eyeglasses?

Does anyone know?

The ratio of the thickness of the glass compared to the unsupported span of material makes them relatively much more rigid than a big, floppy pane of glass. A glass window is not only much less rigid, but also maximizes the surface area that pressure from the blast wave can push against.

This and the fact that eyeglasses are usually not firmly attached to a huge chunk of reinforced concrete.

usually.

Also behind a big glass pane is an enclosed room. Air can rush past the glasses.

Eyeglass lenses are usually made from plastic or polyurethane variants these days, as they can be much lighter, thinner, and tougher than glass with similar-enough optical properties to cover the needs of most eye conditions.

I consider PC a wonder material yet I went back to 1.7 AR coated glass (higher than that it's a bit overkill unless you really need it IMO). It's crisper, actually cheaper, heat resistant and virtually scratch proof if you clean it properly. It's heavier but I'm not going back to finding pinpricks after bouts of wind and all the extra care. The thing about glass is that it can shatter upon impact, plastic lenses won't but basically get ruined all the same in my experience.

I’ve not seem glass as an option recently. I miss having glass glasses for the exact reasons you describe. Worn plastic is scratched and give nasty artifacts.

For camera lenses, they are probably smaller, thicker relative to frontal area, and better protected against shocks and vibrations

Eyeglasses are actually almost always made of dense plastic material these days for better refractive indexes so they shatter differently, also I wonder if physics people consider it to be practically suspended in thin air at the scales of these explosions

Do plastic eyeglasses even shatter? Ever since lenses stopped being made out of glass, the amount of abuse they've been able to take has been through the roof.

I can't imagine a situation where my glasses might shatter before my face would.

They're quite small and thick: https://www.personal-view.com/talks/uploads/FileUpload/77/0c...

Windows break because they're thin and extend over large area, which make them flex a lot.

Similarly, you can see in the video how windows of the surrounding cars are largely unaffected.

Have a look at the vehicle glass in the video.

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