There are different remedies for the target shooter, but for those of us who CCW we're stuck with what we have when going about our daily business.
Many of us shoot the fuzzy sights and it works reasonably well. The principle behind concentrating on the front sight is so that you don't anticipate noise and recoil and flinch, or lower the gun. That principle still works if the front sight you're focusing on isn't in focus. Concentrate on it, anyway. You can still see both the sight and target enough to get on it.
And, you have no choice-- it's always going to be out of focus. Except, as mentioned, for target shooting where you can wear special glasses or use different tools.