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Dust is harder than hard plastic?
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Good glasses are in fact glass with PVD coating, that's where the scratches show up. And yes dust particles are often very hard.

Very few people wear actual glass lenses. They are something like 1-2% of the market from what I can tell. Everyone else wears plastic lenses, which are much lighter and thus more comfortable to wear. Also slightly safer due to much reduced risk of shattering with plastic lenses. I've never even had an optometrist offer glass lenses. I think you'd have to specifically ask for them.

But yeah, dust can also definitely scratch the coatings on glass lenses, too.


Are we still talking about glasses, not contacts right? Because everyone over here (Norway) gets glass lenses in glasses on prescription. They are much better optical quality and not uncomfortable in the slightest, and can be customized to individual vision. Mine have glass from Rodenstock, a long time camera lens supplier but other vendors like Zeiss or Swarowski are common too.

You can always tell if it's glass by tint of PVD coating. Polycarbonate or acrylic lenses can't be coated. Plastic's only advantage is low manufacturing cost.


I have no idea what is common in Norway, but Rodenstock’s English website also says plastic is more common.

Today plastic lenses are considered “State of the Art” and are found in most spectacles.

https://www.rodenstock.com/journal/plastic-vs-mineral-glass

> You can always tell if it's glass by tint of PVD coating. Polycarbonate or acrylic lenses can't be coated.

This not true. Plastic can absolutely be PVD coated. You can buy cheap sunglasses with PVD mirror coatings on plastic lenses. I’m pretty sure Rodenstock’s own plastic coatings (e.g. “Rodenstock technology Solitaire® Protect Plus 2”) are also a PVD process.

> Plastic's only advantage is low manufacturing cost.

And weight. And shatter resistance. And higher refractive index options.


In USA I've been told by multiple glasses sellers (wrongly, but they believed it) that no companies sell glass lenses anymore. It's apparently rare enough that a lot of stores think it doesn't exist.

A large amount of dust is essentially powdered rock, which absolutely is harder than the plastic you would generally find in optical lenses.



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