D.S.
my dd would do (and still does sometimes) a similar thing. she will put a blanket or shirt over her head and walk around and run into things. she does it very slowly and doesn't get hurt...but it's as if she's preteding to be blind. also at mealtimes sometimes she'll squint and close her eyes and eat with her eyes closed.
i posted a similar post on babycenter.com and got many responses saying it was normal at this age...
hth