Re: 15 mins of bluryness
It could be migraine and the blurriness a migraine aura. Look up migraine aura. Often it consists of zigzag lines, but blind spots and other visual phenomena are common. Since you used to get a bad headache afterwards, that's what it sounds like.
If you're getting this everyday, you'd have to talk to the doctor about medication to prevent it, and try to figure out what the trigger is.