You said you practice EMDR, I'm curious about this.. Take a look at this post:
Do you think these issues relate to EMDR?
Interesting post, my first thought based on my own experience is that your eye movements and the practice of EMDR are two separate experiences.
Even though EMDR stands for eye movement desensitization and reprocessing and originally was focussed on eye movements
to recreate a state of consciousness which resembles dream sleep in order to reprocess past traumatic experiences and thus alleviate dissociation,
your eye movements do not seem linked to the above state of mind.
The EMDR therapy I'm currently following is with the use of bilateral tones that are coming through headphones, my eyes are closed.
I will let my optician check my eye movement the next time, as I have minus 9 eye sight both left and right.