Alone in the Dark

Whenever I'm in a situation where I'm walking in the pitch black (like can't see anything black) I find that I walk with my eyes tightly closed rather than leaving them open allowing them to adjust.  I think it's to 'protect my eyes' from sharp pointy objects I might inadvertently walk into in said dark.  More than likely I'll walk into something at shin height, but I still do it.  Every time.  Does anyone else do this?