I see the original post was from May 9th, how has everything worked out. Below are some of my views on the topic.
A white flash in your right what? Eye I would suppose? A little known fact, outside the medical community is that 1/2 of the vision in each eye goes to one brain half, 1/2 goes to the other.
I've had ocular (visual) migraines. There is a shape that is commonly seen during these migraines, known as a scintillating scotoma (colorful blind spot). My migraines appeared to be in the left or right side, but in reality they were in the left or right visual field of each eye.
If I were you, I'd phone the doctor office, tell them what occurred, or ask the doctor to call you when he/she has the chance. The doctor may wish to Rule-out more serious possibilities. Although seizures are a possibility, perhaps anxiety as well, you need to be sure you didn't have a Transient Ischemic Attact (TIA). If you did, you'd need to be treated to assure that you don't have any more.
I've lived through quite a few really weird things over the years, I went blind in one eye twice (came back within minutes, determined to be vascular constriction, not clots), got double vision and did everything but pass out (Basilar Migraine), ocular migraines, irregular heartbeat, all scary stuff and all benign in my case. I also have Temporal Lobe Seizures. When these things first occur, off to the doctor I go.