For a number of years I've had occasional migraine auras but have never had a headache. Maybe a couple of times a year, and it's ages since I last had one. I get an expanding broken circle of zig-zagging scintillation that lasts for about half an hour. I feel a bit washed out for a while afterwards but nothing terrible. I haven't felt the need to get this investigated. One more thing I feel I don't want to be declaring for my travel insurance!