Speaking in terms of eye health, does it matter if the screen is right in front of my eye if the focal length is farther? Or is it still unhealthy?
Assuming that's true, I imagine this would have similar effects.
In fact if those optics weren't there you wouldn't see anything except a few coloured blobs.
The amount of brightness your eyes are ingesting is also much lower than walking around on a sunny day without sunglasses. Remember our eyes work logarithmically so the outside could be tens, hundreds of times as bright.
I've never heard of this actually causing harm though, except some questions were raised about kids whose eyes are still developing. It would be similar to looking through a microscope or binoculars for hours, which is not unheard of in human history (e.g. researchers, lookouts on ships)