I can't stop mine once they really get started, but relaxing makes them less severe. I think I can stop them at a very early stage and sometimes prevent myself from developing into complex partials.
When I'm getting sensory simple partials, like fuzzy feelings, rubbing the affected part seems to help. I think this makes sense. If you think about it your neurons are going haywire and acting disorderly. By giving them intentional feedback through the same circuit it helps them re-organize. They have to process the information, and that makes them work correctly, at least up to a point. My face feels fuzzy, or my hand gets shocks, which is my neurons acting unnaturally. By rubbing, moving, tapping, or shaking the affected part I'm giving it real sensations to process, which requires it to re-organize and act normally. The same thing may be true of your eyes. By not allowing your eyes to do what they want, and forcing them to do what you want, you are re-organizing the impulses.
I went to Andrews-Reiter and found it very frustrating. It was mostly deep breathing, but that never works for me. If I forced myself to sit and do it for 15 to 30 minutes straight everyday it helped, and I felt better, but it was super hard. Nearly all of that time was spent just trying to calm down. The idea was kind of similar to what I said. Instead of giving your body sensory or motor feedback, you are re-organizing your brainwaves to a relaxed state through meditation. Anyhow, Donna Andrews did learn to control her epilepsy, and has taught others to do the same.