Two days ago i experienced a 30 minute display of bright flashing in my right eye with no loss of vision afterwards or during the event. what is this?

It could be migraine: This could have been a migraine aura without the headache but see an opthalmologist (eye doctor) first and if it recurs then see a neurologist.

Depends: This depend and you should consider talking directly with your eye doctor. It may have been a vitreous detachment which is benign but is sometimes associated with a more serious retinal detachment. Usually the symptoms persist in this case. It also could have been an ocular migraine where you will see visual phenomena without a headache for about 30 minutes which then resolves completely.