Posh glasses may well have a UV coating on the back of the lens. Shonky Chinese fakes won’t. Budget brands may or may not.
Coatings only act to reduce reflections, it’s the actual lens material that blocks UV, in exactly the same way that car windscreens block large amounts of UV, making photo-reactive lenses ineffective.
Previous threads have presented info that shows polycarbonate plastics used in sunglasses blocks UV; however, while they might block UV, they may well be pretty crap optically, and distort vision making them very uncomfortable to wear.
Those lenses above are superb optically, the ones in the Frogskins have no reverse coating, only the Iridium-like outer, while the lenses on the WHY8’s have a blue reverse coating, which is generally very good, but can pick up reflected light from my skin, and give back bright blue flashes, which can be a bit disconcerting, despite them being pretty close-fitting.
Other than that, I’m very, very impressed with both company’s lenses, and they’re a God-send for rescuing sunglasses which have been handled badly, (put lenses-down on rough or sandy surfaces), or just dropped onto the ground and the lenses dinged, but the frames otherwise perfect.
Especially when I’ve been quoted anywhere from £90-160 for replacement lenses for Oakleys.