On *Surely You're Joking Mr Feynman*, when talking about the Trinity test, the author states:

> 
> the only thing that could really hurt your eyes (bright light can never hurt your eyes) is ultraviolet light. I got behind a truck windshield, because the ultraviolet can't go through glass, so that would be safe, and so I could see the damn thing. 
> 
> 
> 

This is also clear in [this video](https://www.youtube.com/watch?v=o9BqrSAHbTc), where the glasses are seen as black by the UV camera. If that's the case, why are sunglasses said to `prevent bright sunlight and high-energy visible light from damaging or discomforting the eyes`? *(from Wikipedia)* Is it for marketing purposes or was Feynman wrong?