non-shooting eye problem

[Romeyo]

When I'm shooting precision rifles I typically leave both eyes open as long as I can, making sure all of the fundamentals are taken care of, trying to don't get too much tunnel vision, but as my sight picture gets steady, just before doing the last few breathing cycles before sending the round I close my left eye to be able to focus on the target better, follow thru and see the impact or sometimes even the bullet traveling (rimfire).
However, after quite a bit of shooting vision of my left eye gets blurred. Recovery would take about 10 minutes or so.
After all my eyesight is fine, I don't need any correction devices like glasses or contacts.
I try to close my left eye as relaxed and natural as possible, trying not to squeez my eye shut but it seems to have no noticable impact.

Is this normal, has anybody experienced similar problems and/or got solutions? Should I train shooting both eyes open?

 

[Sterling Shooter]

Why do you think you need to be able focus on the target better? Why focus on it at all? After all, it's the reticle or front sight, given you are properly pointing the rifle with consistent sight alignment, which gives you recognition for where the barrel is pointed. The target is a distraction to establishing sight alignment, as well as an understanding for NPA.

 

[Romeyo]

NPA is adjustet beforehand, as part of my fundamentals list I go through before bringing the trigger finger inside the guard. I somehow feel I got a better sight picture when closing my left eye, or at least I won't be distracted as much by what I see with my left eye.
I usually focus on the target when shooting precision rifles with optics, so I can watch the impact. It helps a bit mentally with follow through I think. Should I shift my focus more on the reticle?
Shooting guns with open sight I of course focus on front sight, but when shooting rifles with optics its a different story (to me)...

 

[mark5pt56]

Stare at the cross hairs. Also, you cause more strain to your eyes by closing one. Someone told/asked me long ago "can you think of any sport at all that requires the closing of one eye?"