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Ignore the die, that's just to tilt the glasses up to more easily see the nose bridge. The rigup totally works, except that over time sweat degrades the heatshrink and it starts to swell. When the rigup was fresh, it was so streamlined that it almost looked factory made, but alas heatshrink doesn't like sweat and body oils.
The exact model is apparently M•Flex ME507. The frames would otherwise be really nice, if it wasn't for the fact that this is the second same set of frames I've had break in exactly the same way.
Could be simple abrasion.
But yeah, lenses aren't eternal. You can make them last longer but they'll age and wear out ultimately. Entropy is a bitch 🙂