I've been writing for some time on my struggles with aging eyes and their effect on my shooting. I'm a bit out of the norm in that my distance vision began its degeneration well before my close up focus was affected. To this day, I need glasses to see sharply more than a couple feet out, yet can see close in without aid. This leads to a lot of time spent taking my glasses on and off throughout the day. Eating a bowl of ice cream in front of the TV is an exercise in frustration; I can either see my food OR the television, never both.
Back in 2012 I began experimenting with mono-vision correction for shooting. I started wearing shooting glasses with prescription inserts. The lens for non-dominant eye was set up with my standard distance Rx, while the dominant eye lens was corrected to bring the focus on to the front sight. I used this technique for about three years, but I was never entirely satisfied with the results.
My dissatisfaction mainly centered around the doubled up lenses in front of my eyes. The two layers of plastic caused some distortion, not to mention added to the weight on the bridge of my nose. During the summer months, sweat would get between the lenses, creating even more issues. The two different focal points didn't cause too much of an issue, my brain worked it out. However, I found I developed the habit of closing my non-dominant eye when shooting. This affected my peripheral vision, and resulted in a lot of blinking during a course fire. There had to be a better solution, but I didn't know what it was.
Then in 2015 I started noticing that the front sight was getting out of focus. My vision was changing and it was time to change the prescription for up close focus. (My distance Rx has not changed significantly in almost a decade.) I also noticed that the front sight of my gun generally sat right at the point where it was now in focus with the naked eye. Every so often I tried not wearing any prescription lenses at the range. I could shoot okay, but I just could not get comfortable seeing distant objects, and people, out of focus. Eventually I forced myself to shoot a match without the Rx. The range bay was small so there weren't any far off things to see, and I shot okay to boot.
The decision was made and from that day forward, I decided to shoot with no vision correction. I accepted seeing the targets blurred, as well as other objects and people in the distance. I know where on the IDPA or USPSA targets the -0 and A zones are located. Even with a partial target, one does not need to actually see the perforations. You don't need to see the target clearly if your sights are in focus and aligned. Hitting a 6" steel plate at 20 yards is still possible even if it's blurred. (I'm never going to be a bullseye shooter.) Focusing on the sight alignment, with a sharp front sight is the secret to hitting the target.
Even people with "normal" vision can't focus on two distances simultaneously, in my case I can't focus at distance at all. Out past about 7 - 10 yards, I can't see the holes in the target so there's no looking for confirmation of a good hit. In retrospect, I truly believe this limitation has helped, rather than hindered, my shooting performance. It's led to a greater concentration on the sights and trigger control. I've long heard the admonition to "call your shots." We even did a drill related to the concept in the Steve Anderson class I took back in 2013. But it never clicked as a real thing until I really couldn't see the hits on the target. Early in the transition I took a lot of extra shots, just because. Sadly, I don't always react fast enough and skip taking a needed make up, and I still occasionally don't call a bad shot.
In the end, I think not being able to look for confirmation on the target has been beneficial. It has forced me to become more confident in my shooting. I've also come to believe that trying to see the hits, as opposed to knowing the sights are aligned, leads to subconsciously peaking over the gun, and shooting low. One doesn't need to see the hit on the target if the gun is on target when the bullet leaves the barrel. After much work, I've also retrained myself to do most of my shooting with both eyes open.
After arriving at the range for practice or a match, I'll take off my regular prescription glasses shortly before it's time to shoot. There's a few minutes of uncomfortable vision degradation, but once I get to the shooting, I hardly notice. In the lower light of an indoor range it's more noticeable. I often use "splatter targets" indoors so I can check out the hits without reeling the target carrier all the way in. And rest assured, I put my glasses back on for the drive home!
I know that my near vision will continue to degrade, and over time I'll require correction to see the front sight in focus. I already see some slight blurring of the front sight on occasion, depending on the ambient light, and where I'm holding the gun. But when that time comes, I'll still ignore making any distance correction for shooting.
I've been warned that I'm a candidate for cataract surgery some day. I figure if I can get my knees fixed too I'll be a "young" shooter someday!