This morning when waking up,saw black ribbon like disturbance in left eye,lasted about 15 minutes,then went totally away & headache came on left side.took excedrin & went away..is this something dangerous? i suffer from many headaches since menopause?

It seems you have a migraine attack with left eye floater as a prodrome. However, if that floater recurs without a headache and you also experience flashing with the same eye, you need to have a retinal exam. You may need prophylactic treatment if you truly have migraine.

This can be anything from a migraine (equivalent) to a posterior vitreous detachment or vitreous hemorrhage to a tear in the retina. You should see an ophthalmologist.