How do I open this light fixture?
Really looks like mine.  Have someone to hold the metal surrounding in place while you turn the glass dome counter-clock wise for a quarter of a circle. The metal edge is in one piece and screwed to the electrical outlet.  I know this post has been online since 2 years, without any answers, although it has 406 views.  So I guess 406 persons do have that same fixture. I hope it help to next 406 persons...  and surely me in a couple of years when it will time to change the light bulb again and will have forget (again) how to do it...