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Thread: EOTech and Astigmatism

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    EOTech and Astigmatism

    Do the EOTech reticles (particularly the 65 MOA circle and the 1 MOA dot) appear misshaped to a person with astigmatism? My only other RDS was a Comp M2 10 years or so ago, and the "dot" appeared to be a star when I used it without glasses. I'm thinking the smaller 1 MOA dot would show less distortion, but that's why I'm asking the question.

    Thanks.

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    I have the same condition. Without correction my red dots, all aimpoints now, appear as commets. When I had the EO, it was the same.

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    Astigmatism causes focusing problems for the eye. When you go to get glasses, the optometrist will determine your eye's ability to focus in that plane (called "cylinder") and your prescription will be ground to correct for that ("better number one, or better number 2"?). Astigmatism will prevent your eye from focusing cleanly on the dot in any RDS without that correction.

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    Thank you, I wear corrective lenses, but sometimes when I shoot I prefer to wear simple protective lenses rather than prescriptive. As a result, I'm looking to choose a RDS that minimizes the effect of astigmatism, if it doesn't eliminate it. Maybe I'll take the chance and try it to see if a smaller "star" is better.
    Last edited by Jwalker; 09-22-11 at 17:40.

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    I think that you are missing a main advantage of the RDS: the ability to wear regular glasses and still engage targets quickly and accurately.

    I wear progressive bifocals which also have a correction for astigmatism and when using a RDS such as the Eotech my regular glasses show the dot as distinct, small, and clear. When I am without glasses, the dot appears larger and vague and unclear in shape.

    My main M4 has the Eotech 556 and the handgun I carry daily is a Glock 22 with a Leupold Deltapoint.

    In contrast, when shooting iron sights, I have a special pair of glasses made which correct the right lens to focus at 25". The left lens is corrected for distance but it is covered with transparent tape to not reduce the level of incoming light. These glasses are just for practice/competition with iron sight handguns.

    For emergencies I want to be able to retain and use my regular, prescription sunglasses and regular, prescription glasses. I do not want to have to find my shooting glasses before having to solve a problem.

    The RDS when used with a correct prescription of regular glasses should have the dot distinct, small, clearly visible, and not mishapen in any way.

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    The other concept is the possibility of presbyopia. People age 45 and older increasingly lose the ability for their eyes to focus at shorter distances due to aging and less flexibility of the eye's lens. As a result, such a 45-and-older person might notice that he can't focus on something as close as a projected red dot sight that's only 3-4 inches from their eye. That lack of focus can cause a comma-shaped dot, or starburst, or some other similar shape. In that case, the focus problem isn't just in one axis due to irregularity of the cornea (astigmatism), but just plain lack of close-focusing ability. In that case, prescription shooting glasses can help, but such close-focusing eyewear can impair the ability to focus at distance (i.e. on the target).Bifocals can be problematic since they're usually designed for reading so the close focusing aspect is usually at the bottom of the lens, meaning that using it to sight a gun means tipping your head back at an unnatural shooting head position. At my age, I've found that 1.5 diopter reading glasses offer the best compromise in that I can focus on a red dot sight, or on the front sight of a handgun, and still see the target well. So I just had some lenses ground at 1.5 diopters over the whole lens. It also gave me the opportunity to get them in titanium frames so that the temples don't dig into my skull when I wear electronic ear protection.
    Last edited by Hmac; 09-22-11 at 21:14.

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    Quote Originally Posted by Team Chuck Norris View Post
    The RDS when used with a correct prescription of regular glasses should have the dot distinct, small, clearly visible, and not mishapen in any way.
    I took in my Aimpoint in at my last optometry check-up/vision test and they said they could not improve my astigmatism with contacts. I don't know if it's possible to do it with glasses but I can't shoot a RDS very accurately past 150 yards due to the blob-ish/spiderweb shape of the dot even with contacts for astigmatism. Granted, it looks a whole lot better than my uncorrected vision, but it is far from a crisp, clear dot like on an etched reticle.

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    Quote Originally Posted by Keesh View Post
    I took in my Aimpoint in at my last optometry check-up/vision test and they said they could not improve my astigmatism with contacts. I don't know if it's possible to do it with glasses but I can't shoot a RDS very accurately past 150 yards due to the blob-ish/spiderweb shape of the dot even with contacts for astigmatism. Granted, it looks a whole lot better than my uncorrected vision, but it is far from a crisp, clear dot like on an etched reticle.
    Contact lenses really can't be ground to correct astigmatism very well since they're round and there's no good way to keep the lens oriented while on the eye to provide good and consistent cylinder correction.
    Last edited by Hmac; 09-22-11 at 21:16.

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    Hmac: ...but just plain lack of close-focusing ability. In that case, prescription shooting glasses can help, but such close-focusing eyewear can impair the ability to focus at distance (i.e. on the target).Bifocals can be problematic since they're usually designed for reading so the close focusing aspect is usually at the bottom of the lens, meaning that using it to sight a gun means tipping your head back at an unnatural shooting head position.
    Thanks, I hadn't considered the lack of close focus to be the problem - I suppose I'm still thinking in terms of scopes and crosshairs which work fine for me. Well, if I don't mount the RDS, it'll be returnable. Again, thanks. If the RDS doesn't work, I'll look for a low power scope, but that's for later.
    Last edited by Jwalker; 09-22-11 at 21:32.

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    Quote Originally Posted by Hmac View Post
    Contact lenses really can't be ground to correct astigmatism very well since they're round and there's no good way to keep the lens oriented while on the eye to provide good and consistent cylinder correction.
    Good to know. Maybe I'll get some prescription shooting glasses so I don't get so frustrated when shooting my Aimpoint at extended distances.

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    I have the same condition, dots always look jacked up to me...I had wanted a TriPower as the etched reticle is crystal clear to me.

    The key is to dial the dot brightness down when possible.

    I preferred EoTechs to Aimpoints for the same reason, for quite a while.

    That said, I had no problem shooting ~1" groups at 50 yards with a T1 (4MOA dot). I'll probably buy an Aimpoint PRO when I get the money to spare.

    It can be distracting, but generally speaking, it's not going to handicap you too much.

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    FWIW, the Aimpoint H1 appears kind of distorted to me (i.e. the comma) whereas the EoTech reticle does not. If I flip up my rear site, however, the Aimpoint dot looks like a dot.

    That's when I'm focusing on the reticle/dot. When actually shooting both look and work fine--or maybe I just don't notice the distortion then.
    "Eyes have been referred to as the window to the soul, we prefer to think of them as the funnel to the brain." - Mike Shertz, MD
    "Every trigger has a match trigger at the end of all the bullshit. - Greg Hamilton

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    My eyes were so bad, when I looked EOTech at the gun show screen were all red.

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