Muzzle Blasts Online
Dec 1999/Jan 2000	Volume 4, Number 6

Pin-Hole Diopter Shooting Glasses

by Don Depew (Drinking Buffalo)

Old shooters never die - their vision just fades away.

It's a fact of life that beyond the age of 40 a person's eyes just can't focus on things as close as his rifle and pistol sights anymore. The condition gets worse and worse as you get older - and it happens to everybody. But you still want to shoot, even competitively, and against those young guys with their young eyes too.

So what can you do? Telescopes work fine, of course, if you're into modern, or slug gun shooting. Peep sights aren't bad, if you're into bench or buffalo. But how do you continue to see those open sights on your offhand gun, or your flintlock, or your pistols? Well, here are some things you can and should do. Try them all and you will be amazed by how well they work. They shouldn't cost you an arm and a leg, either.

The simplest and probably the most significant thing you can do is to use a pin-hole device on your shooting glasses. This will sharpen the focus of objects at every distance. You can buy these, of course, but don't do that. Just use a small piece of black plastic electrician's tape with a 1/16 inch hole punched in it (the smallest size punch of a common leather punch). Pieces of tape no bigger than about 1/4-inch square work fine. Don't make the hole too small, or diffraction effects will make things fuzzy.

Cut a few snips of the tape, punch a hole in each one, and keep them stuck to something inside your shooting pouch, like the top of a cap box. Then if you need a new one, it's all ready to peel off and stick onto your glasses. And that's all you do, just stick it onto your glasses, up in the inner corner for rifle shooting, and more centered but still high up for pistol shooting. If you use small pieces of tape, you can have both stuck onto your shooting glasses at the same time. They don't even get in the way for normal vision.

You really should shoot with both eyes open. I believe that helps stabilize your stance, and helps you subconsciously "pull the shot in" after the hammer starts to fall. Furthermore, it strains your vision to hold one eye squeezed shut. Shooting with both eyes open bothers some people, though, because you get kind of a double image of your sights and bullseye. It helps to put another somewhat larger piece of tape over the inner corner of the non-aiming eye's shooting-glass lens. This should block the off-eye's vision of the sights and bullseye only, not the rest of its view.

So far we've been talking about ordinary shooting glasses, with plain, non-prescription lenses. Apart from their safety aspect, which is essential, of course, our mention of them here is merely for a simple way to locate and support the pin-hole tape. A very significant further improvement in your sighting vision comes by using non-prescription dime-store reading glasses instead of shooting glasses. You select the reading glasses to focus on the front sight, making it very sharp. Your plain shooting glasses (or even your regular prescription glasses) focus on infinity, leaving the sights fuzzy. Your ordinary reading glasses won't work because they focus too close in, for reading. Your bifocals won't work either, because their close-up lenses are too low, again for reading.

Go to your local drug store or big discount store and find their rack of store-bought reading glasses. They will be of several different strengths, generally from 1/4 diopter to 3 1/2 diopters. The diopter strength of a lens is the reciprocal of its focal length in meters. A 3-diopter lens has a focal length of 1/3 meter, about 13 inches. Focal length, of course, is the distance at which the lens produces a burning-spot image of the sun. Most older folks need about a 2-diopter strength for focusing at a reading distance. You will need a little less strength, about 1 1/4 to 1 1/2 diopters, to focus way out there on the front sight of your longrifle or your pistol.

Just try on the glasses and look through them at some fine print held out there at the measured front-sight distance. Select some with big lenses, for safety, and check that the vision is clear while looking through the high inside corner, as if you were holding your rifle. These glasses generally cost about ten dollars, but they are frequently offered for half price. Watch your newspaper for a sale.

Now, with the reading glasses your front sight is sharp but the target is blurry. Not to worry: the pin hole takes care of that. With the pin hole on the reading glasses, the front and rear sights are super sharp and the target is just slightly fuzzy. So what? You're aiming either at the center or at 6:00 o'clock of a black spot. The center or bottom of a slightly fuzzy black spot is just as easy to discern as that of a sharp one. And don't worry that the view through the non-shooting eye is out of focus. With its view of the sights blocked, you're not concentrating on anything it sees anyway. Also, wearing these slightly magnifying reading glasses has the added advantage of helping you see how you're loading or whom you're talking to.

If you do need really strong or unusual prescription glasses for normal distance vision, just wear these additional diopter glasses over them for the slight additional power needed to bring the front sight into focus. Or pay the big bucks to have your optician add two small close-up "bifocal" elements at the rifle and pistol sighting positions of your shooting eye's lens. I've talked to opticians about this, though, and it seems they can't put those trifocal elements just anywhere. You might try making some yourself, by cutting small pieces out of the inexpensive plastic reading glasses' lenses and fitting them somehow where you want them on your regular glasses. I intend to try this someday.

Finally, I presume you've already moved your rear sight farther out along the barrel. Do this, by all means (whether you need glasses or not). It's very important. And don't be half-hearted about it; move it way out there, clear beyond the forestock entrance pipe. The sight can be about 1/3 of the way out between the entrance pipe and the first ramrod thimble and it still looks all right. Don't worry about losing sighting accuracy due to the shorter sight radius. You'll still have twelve to fifteen inches or more, and that's plenty.

While you're moving your sights, you ought to change them too, to optimize the size and shape of the sight picture. There are some really good things you can do in this regard too, but that's another subject for another article.

I've been using these pin-hole reading glasses for shooting for many years. There have been some questions and comments about their odd look (though they are not real conspicuous). I've even heard some grumbling (from grumblers) at primitive events about my using "modern" or "optical" sight aids. Well, I agree that the plastic tape has no place in an ultra-primitive event, and it doesn't have to be there. The first pin-hole glasses I made, years ago, were made by soldering a drilled piece of copper into the corner of an antique granny-glasses frame with no lenses in them. And for purists, old- style frames could be fitted with the needed front sight diopter lenses.

As for modern, I'm sure that if Leonardo da Vinci were a shooter in his day, he would have made himself some pin-hole diopter shooting glasses just like these. The important thing anyway is for all us old-timers to keep on shooting - and these pin-hole diopter glasses will help us keep on doing that. They don't give any advantage over younger eyes, but they sure help overcome the disadvantage (and downright disablement) of older eyes.