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  #1  
Old 08-29-2010, 3:37 PM
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Default Astigmatism and scope question

What happens when a person with AS shoots a rifle with a scope. It seems my POI is not the same as my POA. When my buddy gets behind my rifle he shoots small groups and when Im shooting I get some small but most scattered. The gun is not moving so it has to be my bad eyes.

Are there any type of scopes that work better with an astigmatism? Would an acog be better then a 10x scope?
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Old 08-29-2010, 6:32 PM
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Most scopes have a diopter adjustment. ACOGs, Red dot sights(Eotech,Aimpoint etc) DO NOT.

I have Astigmatism. I spoke to an ACOG rep. once about this,who told me their scopes are made for young eyes! When I look through a red dot sight, I get a 45 degree football, even with my glasses. I still shoot well with them, those of us with Astigmatism are out of luck. I just have to live with it for those types of sights.

My regular scopes with diopter adjustments adjust and allows me to see the reticle clearly.

As far as my POA to to someone else's POI, I don't worry about when someone else shoots the rifle. I can shoot very small groups, my Astigmatism doesn't effect my accuracy in a scope with a diopter adjustment. Without a diopter adjustment, I'm not going to see the reticle or dot clearly and that can affect my groups.

Last edited by FLIGHT762; 08-29-2010 at 6:35 PM..
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Old 08-29-2010, 7:09 PM
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Hmmm

So why would my POI be hopping all over when my crosshairs never leave the center?
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Old 08-29-2010, 9:07 PM
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Unless your astigmatism is severe, it's probably not the problem. The problem could be a related to number of shooter-specific issues: experience, shooting position, trigger control, parallax, anticipating recoil, etc.

Do you wear correction when shooting? how big are your groups vs your friends (give the range)?
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Old 08-29-2010, 9:27 PM
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I have an astigmatism and when I look through red dots they are always blurred. But I got to look through an ACOG TA31 for the first time a few weeks ago and could not believe how crisp and clear it was! The donut and all the markings were clear as day. After that experience I've been saving my pennies for a TA11H.

Traditional scopes with parallax adjustment are better than those without for my accuracy.
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Old 08-29-2010, 9:29 PM
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Old 08-30-2010, 6:17 AM
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Quote:
Originally Posted by problemchild View Post
What happens when a person with AS shoots a rifle with a scope. It seems my POI is not the same as my POA. When my buddy gets behind my rifle he shoots small groups and when Im shooting I get some small but most scattered. The gun is not moving so it has to be my bad eyes.

Are there any type of scopes that work better with an astigmatism? Would an acog be better then a 10x scope?
problemchild,

I have AS really bad and usually have no issues in dealing with the eye condition. If you can't focus on the cross hairs then it indicates your eye is tired and you need to relax and look at something else to focus on for about two to five minutes. Perhaps you need to re-focus/adjust your scope to your aiming eye??? OR maybe your looking too close or too far away from the rear of the scope???? Have you considered those?

Using my red dot electronic sights I onlt turn it up brightly as needed and no more. Too bright not good to little not good either.

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Old 08-30-2010, 8:20 AM
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A few details.

Shooting at 100 yards.
I can on occasion shoot sub 1/2 inch groups.
My trigger is a Geissle Match set to less then 1lb.
Rifle is LMT308
I can group my handloads at 1-1.5 inch sometimes followed by 2-3" the next group doing the exact same thing.
I grouped GFMM yesterday at 2.5 inch.
My neighbor, who has no experience and who has never fired my rifle, shot a 3/4 inch group with FGMM. He also has 20 year old eyes (27).
He grouped my handloads at 1" while I was grouping my handloads at 2"

Bottom line is my rifle was sandbagged for both of us and rock stable. I am very comfortable shooting and never slap the trigger. My crosshairs dont move off center. I taught my neighbor how to shoot using my techniques and he shot sub moa on the second 5 rd group.

It has to be my eyes. I see two sets of crosshairs at the center even with glasses. I can adjust it out but it comes back so I stopped trying. I did look through and Acog and it was very clear but the right side faded off.

Im pretty sure my technique is solid but I am open for suggestion.

Last edited by problemchild; 08-30-2010 at 8:27 AM..
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Old 08-30-2010, 8:34 AM
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problemchild,

Based on your info your eyes are getting too tire when you look through the scope! I believe your staring too long into the rear of the scope. I highly sugget you refocus the scope so it'll be more confortable for you. When you take aim how long do you stare/aim before you take a shot????

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Old 08-30-2010, 11:39 AM
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problemchild,

Based on your info your eyes are getting too tire when you look through the scope! I believe your staring too long into the rear of the scope. I highly sugget you refocus the scope so it'll be more confortable for you. When you take aim how long do you stare/aim before you take a shot????

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I do not think so as it happens right away.
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Old 08-30-2010, 12:06 PM
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Based on your response, I agree that technique is looking less likely. Just grabbing at low-hanging fruit.

GFMM? FGMM? Please explain.

What model scope do you have mounted on that bad boy? Does it have adjustable objective (AO) focus?

How many shots in your group? For just three shots the difference between 1" and 2" may not be statistically significant. I usually shoot a group of five to get reproducible group sizes.

Two sets of crosshairs? That is sometimes what astigmatism looks like when out of focus (I have very weak astigmatismin one eye). Have you tried different diopter settings on the eyepiece? Try to focus the crosshair, not the scene behind it.
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Old 08-30-2010, 1:27 PM
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Originally Posted by bruce_ventura View Post
Based on your response, I agree that technique is looking less likely. Just grabbing at low-hanging fruit.

GFMM? FGMM? Please explain.

What model scope do you have mounted on that bad boy? Does it have adjustable objective (AO) focus?

How many shots in your group? For just three shots the difference between 1" and 2" may not be statistically significant. I usually shoot a group of five to get reproducible group sizes.

Two sets of crosshairs? That is sometimes what astigmatism looks like when out of focus (I have very weak astigmatismin one eye). Have you tried different diopter settings on the eyepiece? Try to focus the crosshair, not the scene behind it.
FGMM= Federal gold medal match (168gr .308)

If adjust for parallax my focus goes out. If I adjust for focus my parallax goes out. I cannot get a focused target, reticle and be parallax free. Bad thing is I am right handed and my right eye is the bad eye.
This is the scope I am using.
http://swfa.com/SWFA-SS-10x42-Tactic...cope-P500.aspx

Last edited by problemchild; 08-30-2010 at 1:38 PM..
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Old 08-30-2010, 3:00 PM
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One last question. Have you properly focused the diopter adjustment for the crosshair properly? Some people don't know how to do this. Reticle focus and target focus are two different things.

To properly focus your crosshair for your eye, you look throught the scope at a blank white wall. You look at your crosshair only and focus the diopter on the eyepiece (rotating it clockwise or counter clockwise) until the crosshair is in focus. DON'T LOOK AT THE WALL! LOOK AT THE CROSSHAIR.

After adjusting the crosshair focus, You can then move the scope to a distant target and then adjust your TARGET focus with the focus knob on the scope at the 9 O'clock position.

I was helping a shooter on our team one morning. He wasn't getting good groups and didn't know what was wrong. I looked through his scope and the diopter(crosshair focus ) was way out of focus. I adjusted it until he could see the crosshair clearly. That was all it was.

You may have done this already, but I thought I'd take a chance and ask.
Just remember,the diopter focus for your eye will be different than your Buddy's eyesight.

When I shoot my friend's Tac Ops Echo with his S & B 5X25X56 P II, I have to rotate the diopter(eyepiece) 1/4 turn or so to get the crosshair in focus for me. After I shoot, I rotate it back to his position.

I hope this helps you.
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Old 08-30-2010, 3:24 PM
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I sounds to me like your vision correction is off. Could also be your shooting position is causing you to use a poor part of your glasses. Do you use progressive lenses?

How old are you and when was your last vision exam?

What do you mean when you say you "adjust for focus"? When I adjust an AO scope, I first adjust the diopter to get a comfortable reticle focus. Then I adjust the objective to get the target in focus. I check for parallax by moving my eye left and right with the rifle resting on bags. If the reticle and the aimpoint stay together, the scope is parallax-free. If the reticle moves off the aimpoint when I move my eye left or right, I re-adjust the objective.

How many shots in your group?
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Last edited by bruce_ventura; 08-30-2010 at 3:31 PM..
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Old 08-31-2010, 3:45 AM
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Perhaps shooting off hand to use the other eye will help you diagnose if it's sight or scope issues?
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Old 08-31-2010, 6:21 AM
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Quote:
Originally Posted by FLIGHT762 View Post
One last question. Have you properly focused the diopter adjustment for the crosshair properly? Some people don't know how to do this. Reticle focus and target focus are two different things.

To properly focus your crosshair for your eye, you look throught the scope at a blank white wall. You look at your crosshair only and focus the diopter on the eyepiece (rotating it clockwise or counter clockwise) until the crosshair is in focus. DON'T LOOK AT THE WALL! LOOK AT THE CROSSHAIR.

After adjusting the crosshair focus, You can then move the scope to a distant target and then adjust your TARGET focus with the focus knob on the scope at the 9 O'clock position.

I was helping a shooter on our team one morning. He wasn't getting good groups and didn't know what was wrong. I looked through his scope and the diopter(crosshair focus ) was way out of focus. I adjusted it until he could see the crosshair clearly. That was all it was.

You may have done this already, but I thought I'd take a chance and ask.
Just remember,the diopter focus for your eye will be different than your Buddy's eyesight.

When I shoot my friend's Tac Ops Echo with his S & B 5X25X56 P II, I have to rotate the diopter(eyepiece) 1/4 turn or so to get the crosshair in focus for me. After I shoot, I rotate it back to his position.

I hope this helps you.
I will try this and post back.
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Old 08-31-2010, 9:07 AM
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OK I adjusted my diopter for scope use without my glasses. Im afraid the diopter needs to go in about 1/2 turn more then it allows. I hit the stop before I get a crystal clear reticle. Also when I adjust for parallax at a know distance the target is fuzzy.

I guess I need to shoot with my glasses on huh?
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Old 08-31-2010, 10:37 AM
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Quote:
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I guess I need to shoot with my glasses on huh?
Uh... yea. I asked you this question in my first post. Starting off with corrected vision is fundamental to good shooting.

The diopter adjustment can only correct for myopia/hyperopia, not astigmatism. It sounds like you have a pretty strong prescription, with a combination of astigmatism and focus correction.

If you're over fifty and haven't had a vision exam in two years, you should get a thorough retinal exam and a new pair of glasses. Shooting high power rifles may put you at higher risk of a detached vitreous humor or detached retina (no conclusive data either way, but why take the risk?).
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Old 08-31-2010, 6:40 PM
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Uh... yea. I asked you this question in my first post. Starting off with corrected vision is fundamental to good shooting.

The diopter adjustment can only correct for myopia/hyperopia, not astigmatism. It sounds like you have a pretty strong prescription, with a combination of astigmatism and focus correction.

If you're over fifty and haven't had a vision exam in two years, you should get a thorough retinal exam and a new pair of glasses. Shooting high power rifles may put you at higher risk of a detached vitreous humor or detached retina (no conclusive data either way, but why take the risk?).
I had an exam 4 mo's ago. Sorry I forgot to comment on your post. I have a pair of maui jim polarized glasses that cost a fortune. Very high quality. I also have a pair of Zeiss clear glasses for night driving.
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Old 09-01-2010, 10:30 PM
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I'm not sure what your point is. Unless the maui jim or Zeiss glasses have your prescription, use your regular prescription glasses for shooting instead.
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Old 09-03-2010, 7:42 PM
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I'm not sure what your point is. Unless the maui jim or Zeiss glasses have your prescription, use your regular prescription glasses for shooting instead.
Yes they are prescription
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Old 08-27-2017, 7:19 PM
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When I lived on Kodiak - I was lucky the local eye doc was also a high power rifle shooter and set me up with a set of glasses specifically for shooting. Today - my new doc is also a shooter, and, when I explain to him exactly which part of the lens I use for shooting, he has tweaked my perscription.

I would recommend you ask around and see if you can find a doc that is also a shooter - and you will probably find them more responsive to your needs.

That - and as you get older, the eye are the first to go. You didnt mention your age - but - from your discription, the days of you buying a scope or sight over the internet are over. You need to get some hands on time before buying.

Most of the additional cost in these better reflex sights are the size of the lenses and coatings. These optics have stronger metalic coatings that take more abuse, and, provide less glare. You certianly can tell the difference between an inexpensive one and high end one if you spend time looking through them allot - most people dont. I have no idea if one would make you less sensitive to astigmatism than another - but - it's an awesome question for you eye doc, and, it would be a very good idea for you to bring one or two relfex sights to show the doc.
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Old 08-27-2017, 7:50 PM
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I don't know if this is a record necropost, but it sure is top 10.
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Old 08-27-2017, 7:58 PM
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back from dead top 10 for sure lol
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Old 08-27-2017, 8:41 PM
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I think I've developed an astigmatism since the OP.
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Old 08-30-2017, 1:20 PM
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Astigmatism is why I'm deciding to dump my T-2 for for an EXPS 3-0, I've been debating it back and forth and I'm 99% sure as of right now.
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Old 08-30-2017, 1:50 PM
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Astigmatism is why I'm deciding to dump my T-2 for for an EXPS 3-0, I've been debating it back and forth and I'm 99% sure as of right now.
I've found EoTech's are WAAAAY worse than a red dot for my astigmatism. The EoTech reticle looks like a giant fuzzy mass of wriggling worms. I had to put it on a home defense shotgun where precision wasn't important.

Everyone's eyes are different. So YMMV. I suggest going to a store and looking through an EoTech before buying just to make sure it works for you.
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Old 08-30-2017, 2:17 PM
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I've found EoTech's are WAAAAY worse than a red dot for my astigmatism. The EoTech reticle looks like a giant fuzzy mass of wriggling worms. I had to put it on a home defense shotgun where precision wasn't important.

Everyone's eyes are different. So YMMV. I suggest going to a store and looking through an EoTech before buying just to make sure it works for you.
Aimpoint's look like a comet to me, the newest Micro's have the least distortion. Eotech's are not distorted but they do have that odd holographic spotting/texture in the ring but that's just how they are normally.



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Old 08-30-2017, 3:13 PM
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Quote:
Originally Posted by problemchild View Post
Hmmm

So why would my POI be hopping all over when my crosshairs never leave the center?

Most likely parallax.

That is one reason why I hate scopes, but my crappy eyesight now forces me to start using one.

.
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