Not sure this is going to make a difference for some of you guys experimenting with red dots, but you don’t focus on the dot itself like you do with a front sight. Most competitive red dot shooters (and I suspect it translates over into other forms of shooting) focus on the target and superimpose the red dot onto the target.
I have mild astigmatism (I wear contacts to see normally plus readers for up close) and I made the switch from irons to red dots a few years ago when I started having problems focusing on my front sight. Changing my shooting from front sight focus to target focus took a bit I admit, but it was well worth it for me. I can shoot iron sight guns, but I need a certain prescription glasses to do so. Since I don’t always wearing those glasses, I put red dots on my carry and HD guns.
This is where you have to go.
All my red dot handguns have back up sights. The sights are there, in the view, every time I look through the red dot and squeeze the trigger. I have to think about it to see the iron sights. Or notice them, maybe a better way to state it. There, but not noticed. Just the target and the dot.
Sometimes I will shoot a group with the back up sights. Just to make sure nothing is "off" from where it should be if I need them. When I'm doing that the red dot is still there, but I ignore it as the sights are a little below the dot (or a lot below on some pistols.)
Up close (at least to 10 or 12 yds. the dot doesn't have to be centered in the lens. If the dot is where you want it on the target it doesn't matter if the dot is at the bottom, top, left side, right side (or anywhere in between) when you pull the trigger. The bullet goes to where the dot is on the target.
Try it. Shoot a five shot group, with the red dot on the same place in the target. One shot with the dot and the bottom, one shot with the dot at the top of the lens, one shot with the dot on the right side of the lens, one shot with the dot on the left side of the lens and the last shot with the dot centered in the lens. You'll still get a nice group (if you and your pistol shoot nice groups with iron sights or with the dot centered in the lens.)
If you want a "red dot" on your rifle with no fuzz, no smear, no sparkle you can buy one of the low powered scopes with an illuminated red dot in the center and that dot will be a nice round dot. I've bought two or three of those over the years and they work fine for my eyes.
Lots of red dots out there. Most anything can work for you to learn to shoot with the dot, most anything can work for range shooting/plinking. If you decide you want one on a self defense pistol, get one that is rough/tough/dependable. They'll be more expensive, but they're tougher and more reliable.
