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The focal length is generally between 95–125cm
Lenses

Pistol shooting correction

07/05/2018
By Michael Grinter
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Pistol shooters require special assistance, but can be a loyal and valuable customer – if you know how to meet their needs. MICHAEL GRINTER explains the secrets to dispensing for this niche category.

As well as being a fun sport, competitive pistol shooting requires great concentration, good co-ordination and excellent vision. Being able to confidently dispense for a pistol shooter is a valuable skill, as shooters are generally very loyal customers, and you may just end up with the whole club attending your practice!

First, you need to define the type of pistol shooter you are dealing with. Air pistol shooting is generally done indoors under fluorescent lighting, with an average range of 10–15m. Alternatively, centre fire and service match competitions can be on a range between 25–50m. This distance is for your knowledge and not crucial to the final Rx we will use.

Setting the RX

The pistol shooter will generally have a basic optical knowledge, either by word of mouth or through having read publications on the subject. This, as we know is a double-edged sword.

What we want to do with the distance Rx, is plus the Rx up to focus clearly on the foresight (front sight) of the firearm, rather than the target.

That’s correct; the target will be slightly unclear at 15m, 25m, and even worse at 50m.

"Even a young, non-presbyopic shooter may need a 0.50 or 0.75 add – even those with 6/6 uncorrected vision."

The focal length will generally be between 95–125cm, and the shooter will understand and appreciate this. They will compensate by adjusting the sights on the pistol to allow them to focus on the divide between the bullseye and the parchment, which is very easy to see, and the pistol will be shooting higher to compensate for this adjustment.

Even after a long competition this will allow your client to retain the sight picture and shoot consistently.

As such, this means that even a young, non-presbyopic shooter may need a 0.50 or 0.75 add – even those with 6/6 uncorrected vision. In presbyopes, the add will be similar to a longer intermediate addition, determined by the measurement discussed earlier.

The patient will need to be reminded that these spectacles are not intended to be worn for any other purpose and won’t be suitable for other activities. Although this may seem strange compared to most visual tasks where the subject requires clear sharp vision at infinity, it works every time.

This advice should not be used for people requiring good distance vision for their professional use of handguns, such as law enforcement officers. It is intended for competition use only, and will allow the competitor to shoot consistently and retain the “sight picture” throughout the competition.

Measuring the distance

Rather than have the patient come into the practice with the pistol, I suggest you ask them to measure the distance from the cornea to the foresight of the pistol they use for most competitions. This can be done easily with a Milliner’s Tape, or a tape measure. It is important that we stipulate the measurement is to the foresight not the rear sight.

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Don’t scare the optometrist, just explain what working distance you require, the same as you would with a person requiring a specific working distance for their daily occupation. To confirm this, you can trial frame the Rx and get the patient to confirm that they can see clearly at this measured focal distance (N12 size print) on a reading card.

Some shooters will use different barrel lengths in different competitions but I usually use an average based on a conversation with them. If for example, the shooter uses a pistol with a 6” and 8” barrel and measured on the 6” (150mm), I add 1” (25mm) to the measurement to give the total as half the difference between the two guns. A familiarity with imperial measurements is helpful as the US is still the biggest manufacturer of firearms.With regard to specific pistol shooting spectacle frames, Knobloch is a popular choice.

Tints

I have made literally hundreds of pairs of shooting specs, and tints that suit one person may not do anything for another individual. In some cases, it’s as simple as the club champion shooting well on a Saturday with purple tinted lenses, prompting the patient to come in and request the same lenses on the Monday.

I always ask that if a shooter wants a certain tint, he or she gives me a sample to match. In all cases I suggest a UV guard and a good antireflection coating. Personally, I don’t recommend tints.

Sometimes the shooter will just give you the lens ring and ask you to glaze it. We should always use datum for centre and physically notch the toric lens with the lens in position on axis.

I like to mark the lens with a sharpie first where the lens ring joins. I then make an obvious groove using a slotting file on the back surface of the lens that coincides with the lens rim joint. This should be easy to see.

The last tasks are to check that the centre of the lens matches the client’s P.D., and to adjust the pantoscopic angle to 90° to the ground, with the subject in normal shooting stance. Use the knurled nut on the frame, or on other models (Champion) the included Allen key, to achieve this.

This method will help create a very happy sporting shooter and a loyal client.

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