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Question re precscription lense for shooting glasses

Posted: Sat Jan 05, 2013 6:59 pm
by jashcroft
My daughter has been shooting with Knobloch shooting glasses with a plano (no power) lense. She wears contact lenses which it has been suggested she should not be wearing for shooting. So I want to order her a prescription lense for her shooting glasses.
My question: her current prescription is -2.50. I have heard we should try to find an optometrist we can take her gun to and ensure she has the correct power to make her front sight clear. Is this over-kill or should I order her normal prescription she lives with everyday.
Thank you in advance for any responses.
John

Posted: Sat Jan 05, 2013 7:21 pm
by Gwhite
The best place to start for pistol is typically +0.75D (diopters) stronger than a distance prescription. That moves the natural focus to about where the front sight is.

Getting the lens from an optometrist that can tweak things while holding the pistol is certainly ideal.

That said, I have shot with contact lenses for decades & never felt it was holding me back. I have astigmatism and wear semi-rigid lenses. It may be that if she has soft lenses, they may not be providing as good a correction as she can get with glasses. If she can see well with contacts, there's no reason I know of to abandon them.

Posted: Sat Jan 05, 2013 9:02 pm
by funtoz
Young eyes are much better able to cope than us older shooters, but it will help to have a lens ground to put the front sight in focus when the eye muscles are relaxed. It will take less energy to do the repeated sight alignments over the course of a match. It also makes peeking at the target an effort rather than the default.

Having a professional produce a prescription is better than just using a rule of thumb that sorta works for most shooters. Taking the pistol in for the test is the best course. That is not possible in some parts of the country because of ignorant paranoia. You may have to use a cardboard mockup if that is the case. The Optometrist can usually set up to do short distance testing. Talk to the optometrist ahead of time and explain what you are trying to do. It turned out that the first time I got a prescription, the optometrist shot action pistol. His replacement some years later had a partner that shot trap. You will probably be pleasantly surprised at the interest the optometrist shows.

There are lots of shooters that get away with wearing contacts, but if she was my girl, they would stay at home. I saw a fellow weld a contact to his eye when home made bore cleaner was splashed into it. I was also on a range when someone blew up his pistol. The person that happened to be walking behind ended up with a piece of brass embedded in his face just below the eye. Accidents can and do happen. An impact resistant lens in the shooting glasses and wrap around safety glass when not on the firing line. If she can't find the door without her contacts, get her a cheap pair of glasses. You've probably already spent thousands of dollars on this hobby, a few hundred more for safe and effective eye wear. sure beats a blind kid.

Larry

Posted: Sat Jan 05, 2013 10:05 pm
by Gwhite
Just because someone wears contact lenses, doesn't mean they don't wear safety glasses. I always wear protective eye gear of some sort when I'm at a range, shooting or not. As a matter of fact, one of my biggest peeves with the filthy expensive shooting glasses Knobloch, Champion & others sell if that they don't provide nearly as much protection as I would like.

Posted: Sat Jan 05, 2013 10:56 pm
by funtoz
I agree about the poor safety of regular shooting glasses. They make me nervous every time I shoot. I switch to regular safety glasses as soon as I finish firing. Wearing wrap around safety glasses behind shooting glasses doesn't work very well. Varga makes a headband lens holder that might work over safety glasses. Its only $105US (as of Friday's exchange). My Knobloch's are getting pretty old, So I may try the headband when I get my guns paid off.

Larry

Posted: Sat Jan 05, 2013 11:02 pm
by Mike M.
Go to www.customsightpicture.com. Get Dr. Toler's kit. It lets you figure out precisely what works. I've used this for the last 5 years, and my only regret was not using it 5 years before that.

Posted: Sun Jan 06, 2013 5:23 am
by jliston48
Gwhite wrote:Getting the lens from an optometrist that can tweak things while holding the pistol is certainly ideal.
I couldn't agree more!

I have had 2 optometrists help me with this situation over the last 35 years - and they both loved the challenge. I just explained my requirements and they were more than happy to help. I guess it is a little out of their day-to-day work and was interesting to them.

Regarding the contact lenses - again the professional is the person to take notice of.

Posted: Sun Jan 06, 2013 9:43 am
by jashcroft
thank you all for your responses. our eye doctor will have nothing to do with it, there is a local doctor with an interest in shooting sports. looks like he will have a new client. once again thank you

Posted: Mon Jan 07, 2013 10:26 pm
by ShootingSight
You don't need no stinkin' eye doctor. Get an eye doctor to get her best distance prescription, as that does take a professional to measure accurately, but the offset between corrected infinity and pistol shooting distance is an exact science that can be calculated, and it is +0.75, so instead of the -2.50, she would use a -1.75. Indeed, eye doctors often do not understand this, you do better by talking to a pro photographer who understands depth of field. Nothing agains eye docs, it's just that the human eye does not 'do' depth of field, while camera lenses do.

You don't need a sight kit. I sell them, but they are not necessary once you understand the lens math. I also sell Knobloch lenses for $40, and it is usually cheaper to buy a lens than to buy a test kit, or pay for an additional doctor's visit.

The only thing to consider is that negative power lenses make the image smaller (de-magnify) as the lens moves further from your eye, so contacts are best for nearsighted people. Now -2.00 range is not that strong, so the shrinkage is not huge, but contact s would be better.

Art Neergaard
ShootingSight LLC
513-702-4879
shootingsight@nuvox.net
www.shootingsight.com