I am 25 and a high myope (-7.25) in both eyes.
I noticed it a few months ago. I had never really moved my eyes in that manner before (i.e. with my eyes closed in the middle of the night).
I have floaters, but no more than before.
I went to a retinal Opthamologist in September 2009. He diagnosed me with Retinal Epithieliopathy (I also see other flashes during the day, which led him to this diagnosis). I am going back in December to see him, in order for him to monitor the progression of the Epithieliopathy.