Vision disturbances can mean a few different things, with dysautonomia (which I also have) it is typically a symptom of the brain not getting the blood it needs. In dysautonomia the blood pools in extremities, depriving the brain of the constant blood flow that it needs. Vision and hearing disturbances are the first sign before you pass out, because the part of the brain controlling those things is the first area to become blood deprived. You may not actually lose consciousness after a vision disturbance, but it is a sign that you're headed that way.
You'd think that if it is a migraine that you'd have pain...I don't have any doubts when I'm experiencing one.
Eye doctors can actually help diagnose IIH which I'm noticing is often associated with dysautonomia. It is too high spinal fluid pressure in the brain, idiopathic intracranial hypertension. This can be detected through eye exams, as the high pressure fluid (often but not always) can cause a bulging of the optic nerve, this is called papilladema. So many Drs have no idea about dysautonomia and associated disorders, and unfortunately in their minds, if they don't know about it, it must not exist.
I get vision disturbances in thr form of peripheral spots most every day, but the type of disturbance changes when I exert myself, and my head feels like a too-full balloon. With exertion I get vision disturbances that looks like my whole vision is covered by a frosted glass grid- that wiggles. Often that leads to a migraine in which I am very sensitive to light and sound.
Do you exercise with compression tights on? I very highly recommend for dysautonomia. Please be very careful with exercising with this condition.