Shooting Glasses

[Lawrie]

I've just had a new lens fitted to my Gehmann shooting glasses and I now find I have a problem. These are glasses I use for .22 target rifle (Anschutz 1813). When I used them for the first time this morning I found that the foresight had gone from circular to elipticle on a horizontal plane.
My lastest prescription (18/11/2003) is (right eye) = Sphere + 1.00, Cylinder + 1.25, Axis 180 degrees, and VA 6/5. Not sure what these figures mean.
Has anyone any idea's what the lens in my shooting glasses should be, and what should the focal point be in front of the foresight?
The optician is not a shooter and I found it hard to explain what exactly I required.
Any help appreciated.
Cheers, Lawrie
lawriew-at-lineone.net.46536.0

[Richard]

My guess is that either the prescription is not quite right for the degre of astigmatism or the lens is not mounted correctly in the holder.
Your position relative to the lens while shiooting is relevant.
govtmodel-at-budweiser.com.46538.46536

[TomF]

Mine go eliptical if I look thru the top inside edge of my glasses. If you are looking thru the optical center, then you have a bad grind. Your optician should be able to see where the center is located.
Or go to a competing optician for a second opinion.
: I've just had a new lens fitted to my Gehmann shooting glasses and I now find I have a problem. These are glasses I use for .22 target rifle (Anschutz 1813). When I used them for the first time this morning I found that the foresight had gone from circular to elipticle on a horizontal plane.
: My lastest prescription (18/11/2003) is (right eye) = Sphere + 1.00, Cylinder + 1.25, Axis 180 degrees, and VA 6/5. Not sure what these figures mean.
: Has anyone any idea's what the lens in my shooting glasses should be, and what should the focal point be in front of the foresight?
: The optician is not a shooter and I found it hard to explain what exactly I required.
: Any help appreciated.
: Cheers, Lawrie

shootingsports-at-ev1.net.46544.46536

[Joseph]

Both comments posted before this one contain flaws.
Basically, the figures you mentioned mean that you are far sighted with a fairly strong astigmatism that is of a degree that is relatively easily correctable. I am less certain of the near/far-sightedness but I am absolutley confident about the astigmatism.
Basically what you ned to do is losen the lens in the holder and (while in position) rotate it until you can easily see the target and front sight without actively forcing your eyes to focus...it should be somewhat relaxed. Also, the orientation of the lens to your eye is of the utmost importance, especially for someone with an astigmatism. You want the lens in a plane parralell to the front of your eye, the rear sight aperature, and the front sight. This is easier than it sounds, there is an optical difference (though less...perfectionist...people may not notice it). Also, you'll want it as close to your eye as possible.
How do I know this? The last time i visited my optometrist, I reached the limit of the calibration of his machines...my eyes can see a difference in less than a quarter minute difference in the axis angle (that's 1/240th of a degree), and it does make a difference (all be it a small one) in my sight picture.
.46556.46536

[Lawrie]

: I've just had a new lens fitted to my Gehmann shooting glasses and I now find I have a problem. These are glasses I use for .22 target rifle (Anschutz 1813). When I used them for the first time this morning I found that the foresight had gone from circular to elipticle on a horizontal plane.
: My lastest prescription (18/11/2003) is (right eye) = Sphere + 1.00, Cylinder + 1.25, Axis 180 degrees, and VA 6/5. Not sure what these figures mean.
: Has anyone any idea's what the lens in my shooting glasses should be, and what should the focal point be in front of the foresight?
: The optician is not a shooter and I found it hard to explain what exactly I required.
: Any help appreciated.
: Cheers, Lawrie


Thanks to everyone for your comments.
I intend to try out suggestions made and will let you know the outcome.
Lawrie

lawriew-at-lineone.net.46557.46536

[Ed Knutson]

Unless I have missed it here, the most important single issue of a corrective lens that has a "Cylinder" component as is used to correct for astigmatism is the ROTATION of the lens in the eyewire. While it is true that the lens should be normal to the line of vision and that you should be looking through the center of the lens as much as possible, the MOST IMPORTANT ISSUE is that the lens is installed with the cylinder axis correctly oriented. This is a particular problem with lenses ground for shooting glasses as they are typically round and can be installed with any degree or rotational orientation. When the lens was ground by the lab, it should have had some kind of index notch made. This index notch is typically at 12 o'clock. This being the case, look to see if you have such a notch and that it is in fact located so that it is at the 12 o'clock position. This means that if you put the glasses on and look in a mirror, that the notch should be pointing straight up when your eyes are level with the horizon. If you tip your head when aiming, the lens must also be tipped so that it is always pointing to 12 o'clock with respect to the level of your eyes.
It is also, of course possible that the lens was improperly ground or prescribed, but these possibilities are far less likely than the above.
Best of luck in solving this.
Kindest regards,
Ed Knutson
the2lts-at-earthlink.net.46587.46536

[mako]

: Unless I have missed it here, the most important single issue of a corrective lens that has a "Cylinder" component as is used to correct for astigmatism is the ROTATION of the lens in the eyewire. While it is true that the lens should be normal to the line of vision and that you should be looking through the center of the lens as much as possible, the MOST IMPORTANT ISSUE is that the lens is installed with the cylinder axis correctly oriented. This is a particular problem with lenses ground for shooting glasses as they are typically round and can be installed with any degree or rotational orientation. When the lens was ground by the lab, it should have had some kind of index notch made. This index notch is typically at 12 o'clock. This being the case, look to see if you have such a notch and that it is in fact located so that it is at the 12 o'clock position. This means that if you put the glasses on and look in a mirror, that the notch should be pointing straight up when your eyes are level with the horizon. If you tip your head when aiming, the lens must also be tipped so that it is always pointing to 12 o'clock with respect to the level of your eyes.
: It is also, of course possible that the lens was improperly ground or prescribed, but these possibilities are far less likely than the above.
: Best of luck in solving this.
: Kindest regards,
: Ed Knutson

.46609.46587