As a former 'squinter' who had 20/20 or better vision and was a good shot, train with both eyes open. It will pay off.
It was a conscious decision to start practicing in a way that was initially uncomfortable, but in the end the practice really paid off.
It took me about a year or two, but I am now better with both eyes open with my pistols than squinting one eye closed. This has led to faster follow up times, and overall better accuracy. And I get the benefits of more natural aiming and natural peripheral vision which allows me to see my shots much more clearly, since I am focused on my target and not the sights/target/sights like when I was one-eyeing it.
I still squint when using scopes, or sometimes for a longer range shot with irons where I'm really taking my time, but almost all pistol shooting is now two-eyes open and I'm a far, far better shooter for it.