Saturday, July 4, 2009

Sight focus and prescription glasses

.

As I get older, my eyesight grows worse. Perhaps too many hours at a computer screen, maybe it's the hundreds and hundreds of books I stick my nose in... maybe just genetics. In any case, I now need glasses to read where ten years ago I could stare down a cat with my steely focus.

The thing is.... a rifle's sights fall into the range where everything blurs for me, both front and rear. This presents a problem when it comes time to actually hit a target, rather than just frightening the ink off the bullseye. Not just me, but alm
ost everyone else who needs glasses to read.

The classic answer is
to switch over to scoped rifles. This eliminates the need to focus on three different planes in the same event, and allows precise aiming. Sadly, the rules of our high power match do not allow this, even for old farts like me. They do allow the use of a single prescription lens built into a peep sight, or a widget that sticks to the shooting glasses and presents a tiny precision hole to sight through. I don't especially like either solution, one altering my rifle, and the other just looking weird.

I know the real answer is to seek out the help of an optometrist who understands the needs of a rifleman. I've heard of one not far away, and who comes highly recommended. Seeing him is on my soon-to-do list. Till then, I wanted to try a little experiment; Shooting with my reading glasses on.

The time honored main method of precision shooting with open sights is to focus first on the rear sight, and then the front, bringing them in alignment. Next the focus shifts to the target, aligning the sights to it, and then the final focus is all front sight, letting the minds natural tendency to line up points take over. Aperture, or 'peep', sights work differently. In those the rear sight just remains a blurred circle, and the mind/eye will automatically try to place the front sight directly in the middle.

To someone who wears glasses to read, without them the rear sight is out of focus, and for some of us the front sight is as well. This makes aiming accurately very difficult. I noticed that both sights come easily into focus while I'm wearing my glasses, and I wondered how well I might shoot that way. Towards that end, an hour at the range with a very accurate open sighted .22 seemed in order.

Going through fifty rounds while making five shot groups, I discovered something interesting. At the fifty yard target line I was able to cut my group size almost in half while wearing reading glasses. Yes, the target was out of focus, but the front sight was sharp and clear.

Moving out to 100 yards, the results took a new twist and group size evened out considerably. I think this was caused more by my poor shooting ability, and the gusty breezes pushing the little .22 bullets around.

I'll just have to go back and repeat the test using one of my 8mm Mausers. Awe Shucks..... that means more time at the range shooting big guns. Rats.

17 comments:

Rick O'Shea said...

My solution to this problem may be worth sharing, especially since it's pretty budget-friendly.

I use reading glasses, and once I found the appropriate magnification (for me, about 2.5X), I bought a bunch of Dollar-Store reading glasses, and have them scattered all over work, the house, the shop, etc...

It occurred to me that I could pop a lens out of one of these cheap glasses and affix it to my shooting glasses.
I use this for handgun shooting, but no reason the diopter power/focal length couldn't be adapted for rifle work.

What I did was use the right-side lens, and use a clear, flexible adhesive to glue it into the upper left-hand corner of the right side of the shooting glasses (confused yet?). The curves of the two lenses will probably not coincide, so the reading glass lens is adhered at its ends, where it contacts the inside of the shooting glasses.

This setup is what I use, and assumes right-hand/right-eye dominant.

Distance viewing is achieved by tilting the head up to look through the bottom half of the shooting glasses, or by looking out the left eye. Near work focus, like doing stuff at the shooting bench or writing stuff down, can be done by tilting the head down to bring the reading glass lens into play.

As mentioned, an advantage to this system is that it's cheap - I use high-impact polycarbonate wraparound safety glasses from Home Depot for shooting glasses, so if I make a gluey, smeared-up mess of a lens application, I'm not out much. I also keep a set of unmodified glasses in my range bag for use with scopes and dot sights.

Sorry for the long description; I should have just sent a picture and said, "Here's what I do"...

Hope this helps someone, though.

Thanks for what you do, Carteach0. I thoroughly enjoy all of your post, and always learn something new.

Regards,
Rick

Broadsword said...

I use my woodworking safety glasses from Rockler woodworking as shooting (and woodworking) glasses. They are Lexan with lenses, cost about $20, are adjustable in two places on the frames, (in-out & up-down) and come in 1x-4x. They are terrific. Glance down to look through the lens and up to see through the rest.

Rev. Paul said...

This may not apply to you, but I've worn glasses since the age of 11. Simple near-sightedness, and has always been correctable to 20/20 or better. Just the same, I've been shooting with glasses for so long that I don't remember doing it without.

The no-line bifocals seem to work well, as the area where the two areas merge provides a small but practical mid-range vision. Because of that, I don't notice the issues that you're describing.

I will admit, though, that I have a bit more difficulty picking up the bullseye at 100 yards than I used to. I can see it okay, but it takes a second longer to focus on it. This geting older stuff ain't for sissies, is it?

Wayne Conrad said...

If it came down to bad times, are you going to have your reading glasses with you, and then take them off when you need to look over the scope and see what's around you?

Scope your rifles and switch venues. The matches are forcing you to train to shoot well for the matches.

Everett said...

Great Post! I'm in the same boat and haven't managed to hit a pirate in the right place recently! But I'll have to wait till all the tourists go home to try out your tricks. Everyone of them on the Island goes BS when they hear a gunshot, and call the local LEO's screaming that there is a war going on. Sigh! SO the bumper sticker of choice says, "Summer People, Summer Not"!

Carteach0 said...

"Summer People, Summer Not"!

BWAHAHAHA! Thanks!

Old NFO said...

Good post Carteach0, I'm now creeping into the same boat, and not by choice... sigh...

pvanderwaart said...

You probably know all this....

The perfect strength of lens for us older folks changes for each distance. For objects close to the eye, it's a big change for even a short difference in distance. For objects far from the eye, it's a small change. I think your eye doctor will tell you that the difference between a perfect lens for your front sight and a perfect lens for the target (infinity..) is quite small, and well within the range that your eye can adjust for.

I need a different prescription to use on the computer than I use to read, but the computer glasses work pretty well out to infinity. The rear sight would be blur, though.

Someone sells little stick-on plastic lenses that you can stick on the corner of your shooting glasses where you will hardly notice them unless actually aiming. They would adjust the strength of the lens up or down a click.

Carteach0 said...

I'll be making an appointment soon with the optomi-doc. (g). I heard of one who is also a high power shooter...

Anonymous said...

Seems a lot of us are in this situation! My own problem has been with the front sight on handguns, rifle sights are still within focus.
I tried shooting handguns with my reading glasses on and had the same issue as described above I probably won't be able to grab my reading glasses in a fight (though they are always with me when I'm clothed).
Tru-glo and Hi-Viz handgun sights have helped somewhat. Ironically it's only my right (dominant) eye that's really losing near-vision. The targets on the handgun range are in perfect focus while the front sight is blurry. The solution thus far has been to discipline myself to concentrate on the blurry front sight instead of the clear target.
I'll be very interested to read what your opti-Dr has to say.
Thanks for a good blog!

Anonymous said...

I read a recent post at RimfireCentral where the poster mentioned just applying a piece of tape with a hole on the eye glass lens was good enough for him for correct - no need for that Merit aperture. Not much better, but a start. And its very inexpensive.

I'm fairly new to bifocals (about a year now), and instantly noticed I have problems focusing with the setup. The 'closeup' lens is too low, forcing me to push my glasses high on my nose when I aim. Not too bad off the hood, but what happens when I'm deer hunting?

When I mentioned this on a post, someone had told me his car mechanic got a pair of spectacles with the bifocal lenses reversed. The close lens is installed on top, where a shooter would need it. Might want to investigate this option when visiting the eye doc. Very natural to me, I peer over top of frame very naturally when viewing very closeup.

Right now, I'm just using my single visions when I go shooting, but I'm sure later on, irons may be a thing of the past. Might have to go Clint Eastwood's 'Unforgiven' character and just use an open choked shotgun, lol.

Hope this helps - you are definitely not alone in this.

Little Joe said...

I started having that problem when I was just past 40. I tried everything and like you I found that the only good solution was a rifle scope.

I hate a scope unless I'm shooting over 300 yards. Always have. Always will.

I finally went to an eye doctor and got fitted for contact lenses. At first it was not much better so I discussed rifle shooting with the doctor. Now I have my regular glasses for reading because I don't care much for contacts. I also have a set of contacts that are a slightly different prescription that I use for shooting purposes only.

I'm not as good a shot as I was when my eyes were young but I'm a darn sight better than I was when I tried to use reading glasses. I also don't have to worry about the glasses getting sweaty, greasy, foggy, etc.

I just put my contacts on when I get to the range and use a plain old pair of safety glasses.

Problem solved for me. I've been shooting like that for over 15 years now. You might ask the doc about that. Contacts are easy to get used to these days. They make soft, disposable, extended wear lenses that last a month and they don't cost a lot.

Good luck,

Joe

ke4sky said...

I've been going through this situation for about the last ten years, and have learned quite a bit in the process, and am willing to share.

For most people past age fifty a shooting glass which puts iron e sights in good focus will be about -0.5 to -0.75 diopter less than your reading prescription. So, if your reading prescription is +2.0 try some drugstore readers at +1.25 or +1.50 and see what the sights look like. Which works best depends upon how long your arms are and how long the barrel is, which affects the distance to the front sight and the required focal distance. I am a six-footer and the distance measured from my cheekbone below the eye to the front sight on my .45 hardball gun is about 39 inches. This just happens to work out close to the same when shooting offhand with an M1 Garand, so until recently I could use Duluth Trading Company +1.25 safety glasses at the range with fine results.

Recently I've been dealing with a growing cataract in my right (dominant - shooting) eye. I required laser surgery last December to repair a detached retina and was told that I would be at risk for developing a cataract in that eye. While the laser is focussed at back at the retinal surface to tack the retina in place while a gas bubble holds it there until it heals, the bubble gradually dissipates over a month or so, putting that much energy through the eye lens induces a point of opacity similar to poking a hot wire in an egg white. It was a matter of how soon the resulting cataract would enlarge to require surgery rather than whether I would get one. My cataract surgery is now scheduled for September, ten months after my retinal surgery. In the interim I have learned to use a Merit aperture over my cataract eye to sharpen the sights, and I shoot with both eyes open, mentally merging the sharp target image from my left eye which has good distance vision, with the right dominant eye which is now severely near-sighted, but aided by the Merit disk.

The corrective plan is cataract surgery and implantation of a flexible plastic interoccular lens which will provide intermediate focus appropriate for using the computer without glasses. It should enable me to see the sights on my carry gun relatively well unaided. I will wear progressive no-line eyeglasses to provide reading and distance correction.

ke4sky said...

I've been going through this situation in stages for about the last ten years, and have learned quite a bit in the process, and am willing to share.

For most people past age fifty a shooting glass which puts iron e sights in good focus will be about -0.5 to -0.75 diopter less than your reading prescription. So, if your reading prescription is +2.0 try some drugstore readers at +1.25 or +1.50 and see what the sights look like. Which works best depends upon how long your arms are and how long the barrel is, which affects the distance to the front sight and the required focal distance. I am a six-footer and the distance measured from my cheekbone below the eye to the front sight on my .45 hardball gun is about 39 inches. This just happens to work out close to the same when shooting offhand with an M1 Garand, so until recently I could use Duluth Trading Company +1.25 safety glasses at the range with fine results.

Recently, at age 61, I've been dealing with a growing cataract in my right (dominant - shooting) eye. I required laser surgery last December to repair a detached retina and was told that I would be at risk for developing a cataract in that eye. While the laser is focussed at back at the retinal surface to tack the retina in place while a gas bubble holds it there until it heals, the bubble gradually dissipates over a month or so, putting that much energy through the eye lens induces a point of opacity similar to poking a hot wire in an egg white. It was a matter of how soon the resulting cataract would enlarge to require surgery rather than whether I would get one. My cataract surgery is now scheduled for September, ten months after my retinal surgery. In the interim I have learned to use a Merit aperture over my cataract eye to sharpen the sights, and I shoot with both eyes open, mentally merging the sharp target image from my left eye which has good distance vision, with the right dominant eye which is now severely near-sighted, but aided by the Merit disk.

The corrective plan is cataract surgery and implantation of a flexible plastic interoccular lens which will provide intermediate focus appropriate for using the computer without glasses. It should enable me to see the sights on my carry gun relatively well unaided. I will wear progressive no-line eyeglasses to provide reading and distance correction.

Anonymous said...

I've been in the optical business for years and figured I'd offer one solution. The near reading portion of a multifocal lens can be placed *almost* anywhere in the lens, excluding the middle of the lens. Go to a privately owned optical shop and tell them you want the bifocal placed in the top left (from your perspective) of the lens and you want the power reduced .5 to .75 diopters to give you a "midrange" power bifocal segment. At my shop a lens like this might cost you 75 bucks or so and would likely be of better optical quality than drugstore readers. To find the ideal spot for the bifocal, put the frame on, hold the gun and line up the sights and put a dot(with a marker) on the lens right at the point that you're looking through. That will be where you want your "round seg" bifocal placed. Make sure you ask for a "round seg" instead of a "flat top" bifocal. That would be my preference at least. Just another option for someone who wants to be fairly serious about it. Make sure you get polycarbonate impact resistant lenses OR 3mm safety thickness in standard plastic.

Scott Wright said...

I choose not to wear glasses. I am using multi-focal contacts. Like all multi-anything there are compromises; everything is not in focus all the time. However, the multi-focal contacts provide a very convenient, always present solution to vision issues on and off the range. Mine are adjusted to provide "very-good"(20/20), not excellent, vision from 12" to about 120 yards. Vision starts dropping off slowly from there to infinity. I have "good"(20/25) vision out to around 1000 yards and "fair"(20/30) from there on. This solution allows me to see both the sights and target clearly.

I am in my late 50's and with out the contacts I need +1.75 reading glasses, distance vision is still very good. I am a network engineer and spend a lot of time looking at monitors and small print. The main issue I have with the contacts is: as the light goes down my vision drops off quickly.

Other options that are available are Lasik surgery. I had my right eye lazed about 11 yrs ago to correct my distance vision, which causes your near vision to decrease as you age. This occurs any how, so no real loss. I understand that there are newer technologies that may correct near and far vision, something you may want to look into.

jimmy1112 said...

At 76 I finally decided that my poor marksmanship was due to guessing where the front sight was. Fixed part of the problem with a cataract operation. Part of the problem because I believe the sight/target picture can still be improved at modest cost. Now in my 40th+ year with glasses, up to tri focals, Considering stick on lenses and stick on pinholes if I can find them. I know there are kits out there somewere!!!