Hi:
Eyeglasses can complicate shooting, especially target shooting. I wear bi-focals and shooting with them is less than ideal. The conventional solutions, optically corrected diopters such as the Ghemem etc. are way too expensive. The eyeglass add on lenses are also quite expensive as are custom ground prescription lenses.
Here's a very inexpensive solution that works for me and may work for you. It's not perfect, but its pretty darn good and the price is right.
Measure the distance from your eye to the front sight with the rifle held normally. Take this measurement to your favorite Dollar Store. You do have a favorite Dollar Store don't you? Go to the reading glasses rack and find a pair of glasses that gives a good clear focus at that distance.
You want the pair with the lowest magnification that works- that is the one with the lowest number on the lens stickerthat will focus without eyestrain. Look away and back again several times. If you focus for any length of time your eyes can compensate and you may wind up with a pair that will cause eye strain. Check your distance vision (10 meters) with them as well. It shouldn't be so out of focus that you have trouble seeing, a bit of bluring is ok.
The glasse you want are the Aviator style, the large triangular oval style worn by pilots.
It's pretty well documented that focusing on the front sight is critical to good shooting, and it's especially true of target shooting. However, if the glasses you got provide too much magnification and focus very sharply on the front sight but excessively blurr the target, you arn't going to hit much. You will need to try a pair with a lower magnification. The right compromise of front sight focus and target visiblilty is what you are aiming for. Try on several pair around the same magnification. I don't think the lenses are ground to very exacting specs. No pun intended.
Go on, give it a try, its only the price of a couple of Senior Coffees at Mickey D's, and all that caffine will give you the jitters when you' re trying for that perfec group.
If you shoot with a notched rear sight, you can place a small circle of electrical tape with a tiny hole in the center on the lense where you look when you shoot. About 1/2" to 3/4" should work. Typically it's near the top of the lense near the inner corner. It varies from person to person, so see what works for you. The "Pin Hole" effect will sharpen up your vision quite a bit. Experiment with the size of the hole, the placenent and the size of the patch. What the heck it's only electrical tape. You can try this on your existing glasses, save a buck in the process and hit the dollar menu.
Bend the ear loops for a firm fit. You don't want the glasses slipping down on your nose, shifting and changing the focus while your are trying to shoot.
If you shoot outdoors, wear a ball cap or a booney hat. The visor/brim will not only shade your eyes but prevent glare from you glasses.
Another aid is to obscure the opposite lense with opaque or translucent tape. This helps some shooters who prefer to shoot with both eyes open but find that it causes problems with the focus in their sighting eye. The opaque tape can be dark or light, usually black or white, which ever works best for you.
Hope this is of some use.
Cheers,
Fatman