Hey, all.

This isn't exactly bang-on topic, but I presume I'll find some wisdom
in here.

I'm an occasional sufferer of ocular migraines. Or at least, this is
what my optometrist says. ;)

The symptom is thus: with little warning, a region close to the center
of my visual field becomes 'null' - normally my peripheral vision is
close to 90 degrees to either side, but when I move my hand to a
certain area of my visual field, it simply vanishes. The size of this
area varies from quite small (tennis-ball sized area in a
basketball-sized visual field) to an entire quadrant (usually
lower-left).

Over the next while (anywhere from 45 minutes to several hours) this
'blob' turns into a halo, which slowly grows out toward the edges of my
visual field, and ultimately dissipates. Shortly thereafter, I get a
mild, dull headache. Not really disruptive, not even really
distracting. But very consistent.

My optometrist tells me I'm lucky, as many migraine sufferers are
bedridden for hours from the pain. For me, it's little more than an
inconvenience, as I can't really see what I'm writing or typing when it
kicks in.

What I'm struggling with is what brings this on?? I've been free of
this for many months, and within the past week I've had half a dozen.
No recent dietary/activity changes to speak of...

Anyone out there had patients with similar complaints, and found any
useful ways to 'nail down' factors which could contribute to this?

Thanks!!

BD.