Suggest Remedy To Prevent Ocular Migraine

How can I prevent ocular migraine? I had them almost weekly for 3 years until last August and they stopped for 6 months. I have now had another 5 of them in 3 weeks. I have tried all the common triggers and it doesn't seem to be any of them. Could it be related to my straight cervical spine? And is there a link to Raynauds too as I have this even in the summer. My hands and feet are always freezing and quite often white.