I used to get those visual disturbances all the time when I was on birth control. A few times I had numbness on one side of my face or one arm. No headache, just the flashing zig-zag line that would start on one side & a blind spot, that gradually took over most of my vision for about a half hour or so. Doc said it was vascular spasms. They've eased off considerably in recent years, which makes me really happy!
umm....crossed wiring?