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Comment by staticautomatic | Hacker News Reader

Maybe it has desirable properties compared to plexi.

Polycarbonate would be a better choice than plexiglass/acrylic. What advantages does glass have? More likely to break and more repairs?

scratches. its all about scratches.

any poly will scratch pretty easily compared to glass, which is a bad thing when its a lens you are looking through. You could make the argument they could just design an easily replaceable poly lens at a reasonable price, but.....its 2024 device manufacturers hate the idea of any user replaceable parts.

The part that is cracking is plastic on the outside glass on the inside, it doesn't get the scratch resistance benefits.

Do you wear glasses or know someone who does? Most of us have plastic lenses with an anti-scratch coating. It works pretty well.

What advantage would there be to switch from plastic lenses for practical items like glasses to glass lenses with a thin soft plastic coating?

I don't, and the couple people I'm close to that do have glass lenses. But, my sample size is pretty bad.

I legitimately didn't know it was that common; I had to switch to glass lens non-prescription sunglasses a few years ago because even the upper end plastic ones weren't durable enough for me.

JerryRigEverything did his usual scratch test with an AVP and the "front glass" scratches with picks of Mohs hardness 3... What kind of poor quality glass is this? Maybe it's just the coating that failed?

You don't have to have a full cover.. Only the cameras would need to have a window of (sapphire)glass. The rest of the ski-mask could easily be plastic, as it's only used to display eyes.

My guess is that it gives them a few cycles to improve the weight. The iPhone X was a monster in terms of weight

Polycarbonate is better in some ways but more susceptible to scratches than plexiglass. Glass is great because unlike the plastics it is UV resistant.

Polycarbonate is great for UV resistance, though not sure that matters for something you use indoors. I’ll grant you scratch-prone.

There are additives and coatings for everything now, and the glass Apple is using is also highly engineered so you can get just what you want no matter what. I’ll bet it comes down to feel and consumer experience.

Only with a UV film installed to protect it. I think all plastics degrade under UV light and polycarbonate is no different. It will yellow and lose it's strength with unprotected UV exposure.

I wore polycarbonate for lenses in my glasses before switching to trivex. Never had a problem with them turning yellow.

Due to a protective coating.

Not so. Sure, everything degrades eventually, but HDPE, PC and acrylic are notably UV resistant, and even polypropylene, which is normally weak in UV, is used in outdoor furniture. Thickness and color matter, but inexpensive UV stabilizers can be added to most plastics as well, and you can get a guaranteed 7-10 years of outdoor life, let alone the sheltered life of a Vision Pro. Source: I make plastic products (sorry, world, that’s why I care about making them well).

Anyway, additives or coating, we agree one can get good outdoor performance with plastics. But forget glass, I’m waiting for the sapphire Vision Edition.

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