Diopter Safety / Shooting Glasses

[jmp45]

Just wondering if anyone has any experience using these for shooting? Irons are fuzzy to my old eyes and this seems to be a possible remedy. I know there's not going to be any fast acquisition but might help get better groups. Looking at a 1.5 diopter.

http://www.amazon.com/gp/product/B000HJMR82

[ShootingSight]

Sorry for resurrecting an old thread - but the topic is still relevant.

The optical math associated with shooting iron sights is analogous to the optical math of photography. A lot of older shooters will tell you it is important to focus on the front sight, but they are, optically speaking, incorrect. It might be good to concentrate on the front sight, but if you are using the optical definition of 'focus', the ideal focal point is actually at the optical average between the front sight and the target. This way, your depth of field is centralized between the front sight and the target, so the front sight is just inside the near edge of your DOF, and the target is simultaneously in the far edge of your DOF, so you can see both at the same time to align them while aiming.

The optical math to calculate the ideal focal point is well established. If I know the distance from my eye to the front sight, and also from my eye to the target, I can calculate the optical average between the two, which is called the hyperfocal distance, and I can further calculate the correct lens strength to shift my eye's relaxed focus there. This way, when I bring up my rifle, my acquisition time is lightning fast, because my eye is already focused in the right spot, and my eye muscle does not strain to get me there (especially for guys over about 40 years old).

Bottom line is that for long rifles, M1, M14, Match, etc, you generally need about a +0.50 lens, and for a 20" AR you need a +0.75 lens. If you have some other iron setup, you'd need to send my the distance from your eye to the front sight, and I can run the math.

I suspect that if the OP actually got the above mentioned glasses, they were less than ideal, because a) they are bifocals, and b) +1.5 diopters is WAY too strong a lens. You'll see a fantastic front sight, but your target will be so blurry that it is useless. The only way to use those glasses is if you try to tip your head so you see the target through the top of the lens and the front sight through the bifocal, but that sucks as a solution both because target acquisition is way slow, and also the images seen through the two lenses will shift relative to each other, as the angle of the glasses tilts slightly, like if they slide on your nose.

In the interests of full transparency, I do sell glasses I have custom designed for shooters, but I do it because I am a HP shooter /engineer /photographer who had vision issues and calculated the solution, and am happy to share my understanding.

Art Neergaard
ShootingSight LLC