I have shot with both eyes open for years and never had issues with following or focusing on the front sight but this morning I put 300 rounds through my carry gun and had terrible issues keeping my eyes focused on the front sight.

When I draw the sights are already right there and I am on target very fast but as soon as the first shot breaks it's like my eyes go out of focus and refuse to come back until I close my weak eye and let the dominant right eye find the front sight. I then would reopen my weaker left eye and it would be fine until the next shot broke, it murdered my drill times and has me wondering if I need to make a trip to the eye doctor.

I am 26 and have astigmatism and have worn glasses since I was a small child but have had no issues seeing or focusing on anything else. I thought it may be some involuntary reaction my eyes are having to the muzzle blast or noise as I have zero issues with dry fire exercises but I have never had the issue before and I put 500-800 rounds a month through various handguns normally. My accuracy was still good but I had to slow waaaaay down and I had to be very deliberate about finding the front sight for the follow up shot instead of it just being there like normal. Not sure what's up but it's killing me.

What kind of gun are you having an issue with? Does that happen with any other one you own? I have a one pistol that gets a little jumpy which slows down my acquisition times. I am not a doctor or stayed in a Holiday Inn, but a trip to the eye doctor might not be a bad idea if you have a problem with shooting over all.

Sig p229 and Sig m11a1, been shooting and carrying the m11a1 for over a year and never had the problem before but the p229 is new. I have not shot other guns to try but I will take some tomorrow and try it just to see.

I'm almost 48.....perfect eyes till 40 then all the sudden astigmatism.

Some days i have to squint my left/non dominant eye to stay focused at all.  
I see two front sights when my eyes aren't cooperating.

Glasses don't fix the red dot/starburst issue for me only co-witnessing with the small peep will........ i see two chevrons in a acog.

I'm not going to be much help other than see an eye doc if your prescription is to far out of whack and learn to work around it.

Have your local gunsmith/machinist take about .020 off each side of the rear sight aperture. 

It it was the answer to my getting older eyes question “Where’s the front sight start and why can’t I focus on it?”

Sometimes I have to close or slightly close my left eye for a split second to focus on the sight.  Most times it is caused by really bright sunny days even with sunglasses it happens to me.  I have always been light sensitive ever since my first concussion and have difficulties even being in the sunlight without sunglasses.  If I go without everything whites out and makes it difficult to see.

For me, I prefer a blacked out rear and a high viz front sight. I prefer fiber optic front but any bright dot on the front works just fine. The blacked out rear let's me focus and track the sights much better.

Try blacking out your rears with nail polish or something and see if that helps. There is a reason this is a popular set up. It works for a lot of people but sights are very subjective. Never hurts to try.

Thanks for all the input.

I went and shot some more yesterday and didn't have any issues, not sure if I should feel relieved or more concerned. I tried my p229 and m11a1 first and everything was fine then moved to my 6920 with aimpoint and it worked fine also. No idea what happened, I am going to go shoot in different lighting conditions this weekend and see if I can recreate what happened a few days ago.

Edit: when I had the issue I was shooting from a dark area into a brightly lit area with night sights.