It's crucial to diagnosing the problem. Check carefully and see if it
"respects" the midline.

If your symptoms stop abruptly at the midline, we can be pretty sure this is
migraine, without the headache. If a brief neurological exam is normal, the
certainty increases. The "classic" visual disturbance is a multicolored 'C'
shape with a jagged or zigzag appearance, but descriptions vary, "like heat
waves over asphalt in the summer."

If it affects both eyes simultaneously, and stops in the center, it
virtually _has_ to be a circulatory disturbance affecting your left
posterior cortex. In healthy young adults with no other neurological
deficit, this is migraine until proven otherwise.

Migraine is a syndrome, a collection of symptoms comprising more than just
headache. 10-20% of migraine attacks don't progress to headache. When
questioned, many will admit some discomfort following each visual
disturbance. Or queasiness, photophobia, drowsiness.

Migraine shows a slightly increased risk of stroke, but so does kidney pie.
On this side of the ocean, with health insurance, doctors will often order a
CT, but insurance companies aren't likely to pay for further testing without
other neurological signs or symptoms. It's still worth getting in line at
the NHS, because there are treatments that may completely control your
symptoms. Read up on migraine and you'll find that each individual may have
their own environmental or dietary triggers (like chocolate) that you can
identify and avoid.

If your disturbance _crosses_ the midline, it becomes hard to believe that
both eyes are affected with exact simultaneity because the arteries leading
to right and left eyes branch apart pretty far back.

BTW, I'm saying "my-graine." I hope you understand I meant "me-graine." :)

-MT