Exactly the same trigger here. I had one just the other day at the pub. Sitting outside, under shade, but to my left was a bright spot. It’s weird how I can sense it arriving ... something about the quality of my vision subtly changes, and there it is.

Fortunately for me it isn’t accompanied by a headache. It’s just really unsettling. At least now I’ve learned to recognise them and I just try to chill out while it does its thing.

(FWIW, also a tremendous consumer of caffeine here. But this was at 17:00, a good 5 hours after my last cup.)

For whatever it’s worth, too much caffeine and dehydration does this to me. Chugging about 48 oz of water and throwing on a face mask for 30-60 minutes usually clears it up. If I do “nothing” it takes significantly longer to clear up.

In my case it's the combination of too much caffeine, dehydration, and intense exercise where my HR maxes out. 2/3 risk factors will typically not be enough to trigger one for me. HIIT workouts and soccer have done it in the past.

The aura (with scintillating scotoma) starts coming on usually an hour or so after the exercise is done, and I know I've got about 15-20 minutes before the actual migraine hits. Got prescribed Sumatriptan and it maybe reduced the intensity by about 25%. I'll have to try the water chugging, maybe with rehydration salts to speed up absorption.

I get the same, and all of these tend to be a trigger for me too -- too much caffeine, dehydration, and rapid light intensity change (like looking outside and then back to my computer screen).

In addition to chugging water and staying in the dark with a face mask, I've found that taking raw honey right as it's coming on makes it go away rapidly.

My long term prevention is taking magnesium daily and LSD once or so a year. Once I started doing that the frequency went to almost zero, and whenever I don't do that they start up again.

I've been getting scintillating scotoma for over 50 years. They've changed character over the years from widespread fortifications to virtually no scintillation at all but always progress from a bright spot to a large blind spot to an expanding toroidal blind region with vision restored at the origin point until they pass out of my field of vision. They used to lead to headaches and sometimes speech deficits or other somatic experiences (like sizzling on my tongue and lips) but now I just get mild abdominal discomfort. With a couple of notable exceptions it lasts about an hour.

I have learned that while they're inconvenient, they're harmless and I just generally continue with whatever I was doing when they began. I have never been able to discern a trigger: they appear to come on completely randomly.

Exact same story here, including the occasional speech problem. Well, I've only been getting them for 30 years. It's always reassuring to hear this from people who have been getting them for longer than me. They used to freak me out when I was younger. Still worry me a bit when I get multiple in a single week.

I've had fewer than a dozen episodes starting last year. Luckily, like you, I have scintillating scotoma without headache. I haven't noticed a trigger--they're just spontaneous. A couple of years before, I had a couple of episodes of binocular diplopia (https://www.yalemedicine.org/conditions/double-vision). Dunno if they're related.

I used to get these two or three times a year, but then I had heart surgery last summer and had five in the first day after I came round from the anesthetic, and two or three every day for weeks after that. They've now settled down to one every few days. Annoying, but they go away fairly quickly and just leave me feeling a bit tired and headachy for a few hours.

Same story for me, had a minor ablation procedure which triggered a bunch of migraines that later settled down.

I've mentioned this before in previous HN threads about scintillating scotomas, but it's worth repeating: in my case, the issue was entirely due to excessive caffeine consumption. When I got them frequently I was sometimes consuming upwards of 450mg/day, when I cut intake way down they disappeared entirely, and when I occasionally fall off the wagon and have way too much that's when they come back.