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Shooting glasses prescription

Posted: Tue Sep 15, 2015 3:46 pm
by GreggoryMoon
I have been shooting for about 4 years now and am averaging low 590s for 60 shot air. I feel like I could be doing a lot better if I had the right prescription for my lens. I have had 3 eye exams in the last year and a half or so and my prescription gets slightly stronger each time, but it still seems way too weak because everything is blurry, in my regular glasses and my shooting glasses. When I'm in class, if I'm farther back than the 2nd or 3rd row, it is very hard to read the board or projector, and even when I am in the first row when I look down at my notes and then back at the board, everything is completely blurry and it takes a while to adjust. If I squint and focus on whatever I'm trying to read very hard it will eventually become clear enough to read. In my shooting glasses, my sight picture is just never clear at all. I have played with my iris size, eye relief, angle of my lens, nothing helps. My regular glasses prescription has gone from :

No distance correction but 1.00 BI prism so obviously no shooting glasses

-0.25 spherical with 1.00 BI prism (no prism in shooting glasses)

-0.75 spherical with no prism.

I've been going to what is supposedly the best optometrist in my area. My insurance covered the last 3 visits which were all within a little over a year since my prescription changed each time, but it's only supposed to cover one exam every 2 years so now I can't go again for a long time. The most recent exam which was only 4 months ago, the machine that predicts your prescription predicted prism, astigmatism, and a much stronger distance prescription, but upon examining my eyes the doctor said I didn't need prism anymore and only needed -0.75 for distance. My glasses do help, but I still feel like they need to be way stronger.

I was wondering if anyone else has experienced anything like this. Do I need to go to a different place and pay out of pocket for another exam, or is it possible I have some other kind of eye issue? It's annoying for everyday stuff but I just deal with it. But for rifle it really bothers me because I feel like I could be shooting way better scores based on how my hold feels and how it looks on SCATT.

Re: Shooting glasses prescription

Posted: Tue Sep 15, 2015 6:48 pm
by gas_gunner
Hi,
I feel your pain. I always feel like I am in the same boat, but more so now. I changed doctors recently. I always had some astigmatism correction in my left shooting eye till now (with the new doctor). Their exam said that I did not need it any longer, but I suddenly noticed shooting problems. My correction was always the very first correction for astigmatism. I suspect, but do not know, that my new doctor "did me a favor" and saved me some money by biasing my prescription to the no astigmatism. I notice nothing in my street prescription, but I notice big problems iny shooting prescription, especially in my ability to read number boards at 1000 yards (I normally need distance correction AND astigmatism correction (unless you believe my new doctor). I notice lately that I have some blurring at all distances, which is not usual. That makes me again suspect astigmatism issues. Correction for astigmatism should correct vision at all distances, not just long or short. You may be in the same boat with me for astigmatism. You might talk to your doctor, explaining your needs, then ask him if you have any need whatsoever for astigmatism correction, even if negligible. If negligible have him bias the correction on the side of writing your prescription for the first correction, rather than not correcting for it. Once you have it ruled out or established that you do need the correction, you can move forward.

Just an idea. I hope it helps,

Danny

*edit* I do not know how good this test is but you might try it. It is free.

http://m.prokerala.com/health/eye-care/ ... m-test.php
GreggoryMoon wrote:I have been shooting for about 4 years now and am averaging low 590s for 60 shot air. I feel like I could be doing a lot better if I had the right prescription for my lens. I have had 3 eye exams in the last year and a half or so and my prescription gets slightly stronger each time, but it still seems way too weak because everything is blurry, in my regular glasses and my shooting glasses. When I'm in class, if I'm farther back than the 2nd or 3rd row, it is very hard to read the board or projector, and even when I am in the first row when I look down at my notes and then back at the board, everything is completely blurry and it takes a while to adjust. If I squint and focus on whatever I'm trying to read very hard it will eventually become clear enough to read. In my shooting glasses, my sight picture is just never clear at all. I have played with my iris size, eye relief, angle of my lens, nothing helps. My regular glasses prescription has gone from :

No distance correction but 1.00 BI prism so obviously no shooting glasses

-0.25 spherical with 1.00 BI prism (no prism in shooting glasses)

-0.75 spherical with no prism.

I've been going to what is supposedly the best optometrist in my area. My insurance covered the last 3 visits which were all within a little over a year since my prescription changed each time, but it's only supposed to cover one exam every 2 years so now I can't go again for a long time. The most recent exam which was only 4 months ago, the machine that predicts your prescription predicted prism, astigmatism, and a much stronger distance prescription, but upon examining my eyes the doctor said I didn't need prism anymore and only needed -0.75 for distance. My glasses do help, but I still feel like they need to be way stronger.

I was wondering if anyone else has experienced anything like this. Do I need to go to a different place and pay out of pocket for another exam, or is it possible I have some other kind of eye issue? It's annoying for everyday stuff but I just deal with it. But for rifle it really bothers me because I feel like I could be shooting way better scores based on how my hold feels and how it looks on SCATT.

Re: Shooting glasses prescription

Posted: Wed Sep 16, 2015 12:12 am
by ShootingSight
Note that doctors correct your vision so your relaxed eye will focus at infinity. You then need to exert the eye muscle to bring your focus in closer in order to see the front sight. If you are straining with adjusting your focus (as a lot of older people do, who need reading glasses), the better solution is to do the optical math to figure out where your eye really needs to focus to see the sight and the target together, then calculate the lens you need so your focus is just adjusted to that spot in the first place.

This magic location, located at the optical average of the front sight and the target, is called the hyperfocal distance in photography. Photographers get this concept, because they use it to set depth of field in pictures. Eye doctors will have studied it in optical theory class, so they know what it is, but have never applied it to human vision, because as far as I can see, sooting is the only time human vision is trying to see nearby objects (sights) and distant objects (targets) at the same time.

So, bottom line is that for ideal vision in a long rifle (over 27" between your eye and the front sight), you want to take your distance prescription, and add +0.50 diopters to it. So if you are a -0.75 distance prescription, you would want a -0.25 for shooting. If you have good distance vision, and only need help reading (ie you need 0.0 - zero to see distance), then a +0.50 lens is the right answer. If you need a -0.50 for distance, you can shoot with no corrective lens at all!

For shorter rifles, like AR15, or for pistol, people generally need to add +0.75, because the sights are slightly closer.

So, next eye visit, ask for your prescription, then add +0.50 to it, or +0.75 to it, and get that lens made for shooting.

Note: I am an engineer who has studied optics and photography. I am not a doctor. So I can do lens calculations to optimize your focus, but if you have a medical condition, do not rely on anything I say - see a real doctor.

Re: Shooting glasses prescription

Posted: Thu Sep 17, 2015 8:11 am
by Ed Hall
Although he's a pistol shooter, Dr. Norman Wong has written a document designed to help other eye professionals understand our needs as shooters, that would probably have value for rifle as well. You can find this info, including a .pdf version that can be taken to your eye care professional here:

BULLSEYE SHOOTERS' GUIDE FOR THE EYECARE PROFESSIONAL

and more articles by Dr. Wong, here:

Dr. Norman Wong Articles as posted to the Bullseye List (plus*)