I don't believe it. I have this pair of safety glasses I bought from the hardware store for $5 and they are super light weight and rock solid. I could wear them all day and not even notice. Sometimes I even forget I am wearing them and wear them around inside for a while when I'm finished my work.

If they had some tint and UV protection and I would consider using them as shades.

update: I talked myself in looking at the hardware store website and my next sunglasses will be be some 3M safety glasses with a dark tint and uv. And less than $20.