I was misdiagnosed with migraine. 24/7 pain centered behind my left eye for 18 months. Tried every migraine medication, nothing helped because it wasn't a migraine. Vertical heterophoria and aniseikonia meant my eyes weren't seeing things the same. Eye strain from trying to get the images to merge and brain fog due to all the extra effort devoted to just seeing. If eye pain is associated with your 'migraine' start at the website Could It Be My Eyes. This may only be the case for a few of you, but finding that site put me on a path to relief. A half-dozen optometrists and 3 neurologists failed to identify this. Prism glasses fixed the vertical heterophoria. The aniseikonia is much more rare and discovered during treatment of the former. Headaches are a thing of the past and most of the eye strain is gone. (Still tweaking the glasses.)