Hey, you know what?.. My case is pretty similar to yours.. My
boss was my ex-colleague as well. The only difference is that my
boss & I are like buddies. Trust is built based on
communications.. of any kind.
May I suggest that you tell your boss how you feel. It may sound
scary, but this is probably the first step to take, if you want
things to change. try to create an atmosphere for this
communication to happen, say at a pub, at lunch, or whatever that
you may deem fit.
Performance appraisals are based on deliverables, and not how well
your boss knows you. This is what I tell my guys during their
appraisals as well.. If they dun tell me what they want, or aspire
to do.. I wun know how to put down good words for them, when it
comes to ranking..
Hope this helps, buddy.. 
