You've been 'successfully' shooting for 30 years. You are right handed. Your left eye is your 'dominant' eye. The solution is easy - close your left eye and shoot. Done. That's it. Doesn't matter if you are shooting a shotgun, rifle, or pistol. When you close the "dominant" eye, the brain is perfectly happy to use the non-dominant eye for the task at hand. For people that can't WINK (close one eye) putting scotch tape over the lens of the eye not being used accomplishes the same thing (forces the brain to 'use' the non-dominate eye for the task at hand.)
Cross dominance is not uncommon. The guy that ran the skeet range I shot at was cross-dominant and shot with one eye closed to 'fix' the issue. He was consistently breaking 23+ targets every round. Drove some people crazy ("You gotta shoot with both eyes open!") but life isn't fair and we do what we have to do to even up the odds when given a poor hand. Thankfully for you, that only means you have to close your left eye when shooting from the right side...probably like you've done for 30 years. Don't change anything. You've adapted and are successful.
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Before closing, I will add this: Some people have a condition called AMBLYOPIA. This means one of their eyes never developed the ability to see more clearly than 20/40 (and some see much worse than that). The clearer seeing eye is their DOMINANT eye, but they don't have the option to close that eye and use the other (amblyopic) eye for shooting, because the visual acuity is not good enough. These are the folks that MUST learn to fire from their 'dominant eye side', and that is not an easy task, but it can be accomplished with some practice.