About six months ago I had surgery to repair a detached retina. I had a follow-up appointment today with the surgeon. In order for him to check out my retinas, my eyes had to be dilated. The retina is fine, but the dilation required me to don my prescription sunglasses, even indoots, and gives everything a hazy, gausy apperance.
I also got the slide for my full-size PX4 from Langdon Tactical today. I had sent it to Ernie for installation of the Ameriglo sights he offers as well as converting the stock safety to de-cock only. I decided to take the PX4 to the range after the appointment in spite of the impaired vision. Worst case, I'd burn through five mags of my carry ammo (124 grain +P HST) to further vet the gun.
I could see well enough to verify the zero and it was right on; I may need to tap the rear sight a hair to the right, but I'll check that again when my eyes are normal. I ran several different drills, mostly using an IDPA practice target. The main takeaways are that at close range (three yards) there's no noticeable degradation of accuracy, while at medium range (seven yards) the larger -0 was no problem but hitting the four-inch -0 in the head box required more slowing down than usual. I also ran the Hackathorn Test at ten yards and ended up with a 93; the front sight was much easier to see against the black B-8 bull.
The bottom line for me is that even if you have somewhat impaired vision, you can still make good COM hits if needed.