Sometimes when I am indoors (doesn't happen outdoors) it seems like light is suddenly turns off for a tiny moment, like there are problems with electricity. Mostly it happens at home but today I noticed it when I was sitting in a cafe. It appears to be random, sometimes I notice it twice a day, some days I don't notice it at all. I have myopia (not too bad, around -4), but no documented brain disorders. I also wear contacts, but I started to notice it before I started to wear those (used to wear glasses for 7 years until October 2010). It's been going on since September or so, doesn't seem to get worse. Also, I am 18 years old. Should I be worried? Thanks in advance.
PS Sorry for english, not my native language.