Hello, and welcome to Mayo Connect. We are a community of patients and caregivers, living our best with a wide variety of conditions and diseases. We are not medical professionals, and cannot provide medical advice, but we can share what has and has not worked for us.

You have already taken the first step - to do your research. This is another source for information. https://www.aao.org/eye-health/diseases/what-is-nystagmus

I have had experiences with eye shifting, and in my case, the doctors were able to attribute it to inner ear disturbances, which also give me vertigo (dizziness.) As a matter of fact, the involuntary eye movement when trying to read often is my warning that a bout of vertigo is about to begin. At that point, I do a series of anti-vertigo exercises for a few days and it usually resolves. Do you ever experience vertigo?

With the sudden onset, you may want to consult an ophthalmologist to see if a cause can be determined, such as a head injury or a previously undiagnosed eye condition. Also, it may be helpful to keep a diary of all the things you eat and drink and all drugs or supplements you use, then track when these episodes occur to see if there is a correlation. (Hint: it may not happen immediately - there could be a lag between a specific thing you ingest and an episode.)

Perhaps there are more people here with additional suggestions.
Have you asked whether anyone else in your family ever has this happen?
Sue