DaisyB, that is exactly what happened to me in June 2004 when I had my first attack, I woke up and had shimmering, zig zaggy lines (scintillating scotoma) for about 25 minutes and they gradually disappeared to the upper, outer sight field - I do not get headaches either. I had a Mirena coil when I had my first silent/optical migraine and I now know, many years and many specialists later, that is was caused by the synthetic progesterone in the coil combined with my own very low levels of oestrogen. To be honest, I didn't ever do well on synthetic progesterone pre-menopause but it didn't cause migraines until my oestrogen levels dropped.
I now have to be very careful to make sure that my oestrogen levels remain quite high and I also have to seriously limit my use of (vaginal) Utrogestan and can only take the very barest minimum. I have also found that daily DHEA tablets have really helped and at least if I do have an attack, it is much less severe and I don't have the postdrome. I have been told that I should have a hysterectomy so that I never have to use progesterone again but work makes that difficult at the moment.
Progesterone changes the way your brain receptors work and that is why you get migraines - synthetic progesterone is the worst offender and I once had 5 attacks in one day while using norethisterone.
Salad, if you now take oestrogen only HRT and you no longer have migraines, it sounds like progesterone was the culprit in your case too. Have you had a hysterectomy?
I hope that helps.
