Not to beat a dead horse, but most eye exams don't tell you much about shotgunning. Dominance can change with fatigue, stress, hydration etc. I would trust a really good coach over an eye doc for most shooting issues. In the same way, any bad habits can be reinforced (checking lead, moving too high on the target line, and others) can come and go as an issue as our subconscious strives to sort perceptions and visual reality. Best of luck and hope you just had a slump and don't have to face the challenges others mentioned. I once missed 90+% of my L8s in a harsh Kansas winter back in the early 1990s because my occluder shifted when I shouldered my gun with a winter shooting jacket. I never would have believed it and it took over three months for my eyes (brain) to catch the visual shift occur in my mount.