My aura's are perhaps similar to tigertiger's. I am a 64 year old male. I have almost no headaches - maybe one a year. No migraines. I take only a blood pressure medication, but the auras started before my blood pressure problem started.
My first aura was maybe 15 years ago and I've had an average of one or two a year since then. Only a few have occurred as often as daily. At the time of the first one, I had no idea what was happening or what the cause was. A nurse at work found a book with a 1-paragraph mention of visual auras. After my third aura, I kind of figured out that they were associated with my eating perhaps too much of one particular type of onion greens. A few days ago I had one shortly after eating a 1/3 pound microwaved onion. Maybe I just like onions too much.
The aura is difficult to describe. Mine have all been visually similar, identical for both eyes, and sometimes I get a mild dull ache in the back of my head near the end of the aura, lasting maybe 1/2 hour. All of the auras start out as a blanked out place just to the left and below the point I am trying to focus on. The blanked out area is medium gray. On my computer desktop, the icon I focus on is just not there, but all the icons around it are visible and perfectly readable. Within maybe 5 minutes, the blanked-out area has about trippled in size, but now has some features. The main feature is a bright white line, kind of C shaped. The top of the C is kind of horizontal and the left side is kind of vertical, and the bottom is kind of horizontal. The whole line of the C is very crooked - kind of jagged all along its length, something like lightning, or a sawtooth wave. The crookedness seems to constantly be changing, and but I can't see what exactly is changing. The top and left are well defined and the bottom is less-well defined. The blanked out area is the area close to the C-shaped line. Over a period of about 1/2 hour, the C expands and becomes less well defined, until it is out of my field of vision. Since the blanked out area is a narrow area near the line making up the C, about 10 to 15 minutes after the start, the icon I focus on is perfectly visible and the jagged C is around it and the icons outside the C are perfectly visible.
Because I am a procrastinaor and the aura's haven't upset my life much, I have not had them medically diagnosed or treated.