The Flash of...?

Well, this strange thing happens, not very often, once every few months-ish, there is a blinding white/grey/lightblue sort of magnesium buning kind of flash that starts small in the centre of my vision and expands untill it takes up my whole field of view.. although this only lasts milliseconds at most, its still strange enough to get me thinking (and for those who dont know me, it takes something very sick, strange or interesting to make me think in the slightest)

does anyone have the same experiences? anybody know what it is or why its happening?

You're probably going to die... (Hurrah for optimism)

I suggest that you write in a notebook(no Chris not a death note just a regular notebook) every time you experience this too see if there are any interesting patterns such as it happens at set times or anything such as that. i'm sure your not going to die by the way