Blinders — Pinhoe TSC Training Library | Pinhoe Target Shooting Club

Introduction

This article is relevant to members of all our disciplines, experienced or otherwise. It has areas of controversy, particularly where science confronts established practice. Let the debate begin.

What are blinders?

Blinders are devices that shooters place in front of their non-aiming eye to prevent that eye from sending image-forming information to the brain.

Key Concept

This definition does not say a blinder stops all visual information reaching the brain. It blocks the image, not the light. As we will see, that distinction is the entire point.

Blinders come in different shapes and sizes. They are either attached to your head or to your firearm.

Types you will see at the club

You will see four common types of blinder in regular use at Pinhoe TSC:

Glasses-mounted — clipped onto, or built into, a pair of shooting glasses, sitting in front of the non-aiming eye.
Cap-mounted — a small flap that attaches to the peak of a shooting cap.
Sight-mounted — fixed to the rear sight, either by a magnet or threaded onto the peep-sight aperture.
Head-band — a strip across the forehead with an opaque flap covering the non-aiming eye.

Tip

You can make your own from an opaque plastic milk carton and a pair of scissors. The carton must be opaque — a translucent one defeats the purpose.

How do our eyes work when we are shooting?

This part gets a bit technical, but bear with me.

Watch somebody shoot a firearm for the first time and you will notice they instinctively close their non-aiming eye. Why?

Try this — the finger experiment

Try it yourself

Extend one arm with your index finger pointing upwards. Focus on the finger. Close both eyes and bring the finger to about 10 cm from your face. Open your eyes. How many fingers can you see?

Now hold that position and refocus to produce a single, one-finger image. Within seconds your eyes will start to ache. The rectus muscles that move your eyes in their sockets are working hard to keep both eyes pointing inwards at the same time.

Our eyes work as a pair. What one does, generally the other does as well. The brain combines the messages from both to produce 3D, or stereoscopic, vision — that is what lets us judge distance accurately.

It has been estimated that up to 50% of the brain’s processing power can go into the concentration needed to keep an object in focus when the eyes are not relaxed. So not much is left to manage the rest of your shooting technique — or even to chew gum.

The iris muscles of our eyes contract and relax to alter the size of the pupil depending on the amount of light. This extends the range of lighting levels in which our eyes can safely operate. Usually, the iris of both eyes contracts and relaxes simultaneously.

Try this — the pin-hole experiment

Try it yourself

Push a pin through a small dot on a sheet of paper. Find a page of printed text. Bring the page towards your face and stop when the writing goes out of focus — note the distance. Now hold the pin-hole close to your eye and look at the same page. You can read the writing much closer. Looking through a small hole increases your depth of vision for that eye.

So when we look through our sights, three factors come into play:

The amount of light entering the shooting eye
Our 3D vision
Our depth of vision

All three are different for the shooting eye and the non-shooting eye. How is the brain meant to deal with six different sets of data? The composite image it produces (we see with our brains, not our eyes) is a rather poor compromise.

The first reflex — closing the non-shooting eye — causes its own problems. The closed eye tells the brain it is dark and opens its iris; the shooting eye tells the brain there is plenty of light. The brain compromises, partly opens both irises, and the shooting eye no longer has enough light. The iris of the shooting eye (which is just a hole) cannot achieve sufficient depth of focus to hold a sharp image of the foresight, and the eye muscles tire trying. Accurate shooting cannot be sustained for long.

An opaque blinder solves all of this. Light still enters the non-shooting eye from around the edges and through the carton itself, so the iris conflict between the two eyes is resolved. Depth of focus is no longer a problem. And the brain has only one image to resolve, because the non-shooting eye — while receiving light — sends no image data.

So, who should wear a blinder?

This is the controversial bit.

Note

The science says all target shooters should wear a blinder.

Look around our disciplines, though, and you will find this is not always the case. Prone shooters wear them routinely, though they may not know why. How many of our LSR and benchrest shooters use one? If not, why not?

Looking through a scope does not alter the biology of our eyes or the workings of the brain. That said, I could not find a single picture of a high-end LSR or benchrest shooter using a blinder. I would love to hear from anyone with more hands-on experience in those disciplines as to why this is.

For visually-impaired shooters, competition rules and equipment guidance are governed by the disability shooting bodies — speak to your Head of Section or the Training Officer if this applies to you.

Happy and crystal-sharp shooting to you all.