So does the Sun.

Also, you never look at the light directly.

The sun's spectrum is relatively smooth, whereas there are some grow lights that have a narrow, intense spike of UV designed to match chlorophyll B's absorption. Not all grow lights have this spectrum, but it's worth being careful. It's one of the reasons why some grow lights come with a warning about using eye protection.

That's a good point, although I'm pretty sure the Sun still trumps any kind of LED grow light output, especially during summer months.

That being said, maybe it's a good idea to use a plexiglass UV filter when using it as a workshop light.

My understanding is outside, your pupils will dilate as the light increases, protecting your retina from increased UV. If you had a strong emitter of UV in a relatively dim room, your pupils wouldn't shrink and would allow more damaging UV to hit your retinas.

I'm not sure where you got this understanding from, but the LED lights I'm talking about (grow lights) are definitely bright enough to make your pupils shrink.

> If you had a strong emitter of UV in a relatively dim room

A 150 watt LED right above your head is the opposite of dim.