Basic instruction introduces this subject to beginning shooters, but without much follow-up. We asked Dr. Norman Wong—Master Bullseye Pistol shooter and optometrist, for a medical introduction, followed by the shared experiences of nine champions.
Dr. Norman Wong “Shooters should understand the physiological changes within our eyes, whether we choose to close (or occlude) our non-aiming eye or not. The reason for closing or occluding is to prevent diplopia (double vision) as we obtain our sight picture.
“The sympathetic nervous system (SNS) and the parasympathetic nervous system (PSNS) are part of the autonomic nervous system that controls our body. Within the SNS, we’re concerned with the iris dilator muscle—a smooth radial muscle that dilates the pupil. The pupil dilates automatically when, for example, there is a ‘fight or flight’ response and when the light is dim. Conversely, within the PSNS, the iris sphincter muscle constricts the pupil. If one were to compare the human eye to a camera lens, the average eye has an ‘f stop’ of f 5.6.
“As many know, our pupils constrict with bright lighting. With each millimeter decrease in pupil size, our depth of focus improves by 0.12 diopter. When a light source is directed onto one eye, the pupil of that eye constricts. This is known as the “direct light reflex.” Interestingly, the pupil of the opposite eye also constricts, which is known as the ‘consensual light reflex.’ Of particular interest to the shooter, when we close the non-aiming eye while shooting, not only does that pupil dilate because of the diminished lighting, but so does the pupil of the aiming eye.
“With a larger pupil, we may not see as well for a couple of reasons. As the pupil size increases, the depth of focus within our eyes decreases along with a corresponding decrease to the depth of field. Although our front sights may be clear, the target will become more blurred. Secondly, when the pupil is larger, all of the light rays may not converge onto the retina in a single point because of spherical aberration. There is spherical aberration as light passes through both the cornea and the crystalline lens. With younger shooters, the positive spherical aberration from the cornea is compensated by the negative spherical aberration from the crystalline lens. This is another reason why younger eyes see better than older eyes. With aging, spherical aberration from the cornea remains constant but the spherical aberration from the crystalline lens changes, causing more focusing problems among older shooters.
“Why does closing or using a dark occluder over our non-aiming eye seem to affect some of us more than others? One of the main reasons is our individual pupil size. At one time, it was thought that myopic eyes (nearsighted eyes), blue eyes, and women tend to have larger pupils; whereas hyperopic eyes (farsighted eyes), brown eyes, and men tend to have smaller pupils. Recent studies have indicated that these factors may not be significant, but age has always been a determinant of pupil size. As we age, our pupil size decreases and the pupillary response becomes more sluggish. When a shooter under the age of 40 focuses on the front sight, the pupils constrict naturally, a principal known as the ‘accommodative reflex.’ The accommodative reflex is diminished or absent with older shooters. With such a variety of situations, so are our own interpretations of how blurred the target appears. A shooter with a 6 mm pupil will see differently than a shooter with a 3 mm pupil.
“Within reason, we would generally like to allow as much light as possible to reach our eyes to keep the pupils small. Besides causing the shooting eye to dilate, closing the non-aiming eye may also cause the eyelids of the shooting eye to tighten and alter vision. If the shooter chooses to use an occluder rather than closing the non-aiming eye, she can maximize the lighting to that eye by using a white, translucent occluder or scotch tape, rather than a black occluder.
“Conventional pistol shooters and the majority of rifle shooters are static in their shooting positions so a variety of methods may be used. Other disciplines that require quick movements may not benefit from occluders which would limit peripheral vision. While experimenting, some shooters may find that they can keep both eyes opened while shooting—aiming with the dominant eye while ignoring the non-aiming eye, without the use of an occluder.”
“Even with all this knowledge about our eyes, we still need to keep things in perspective. Jim Lenardson, a past national conventional pistol champion, shot his iron sight pistols while he simply closed his non-aiming eye. Other notable pistol shooters such as Philip Hemphill, 10-time winner of the National Police Shooting Championships; Dave Lange, past civilian national conventional pistol champion; and SSG John Ennis of the AMU pistol team have all used a black occluder. Five-time national conventional pistol champion Steve Reiter writes: ‘I have a black patch for my left eye. Sometimes I wear it, and sometimes I don’t.’”
And from our Expert Panel
Jessie Duff—National Action Pistol Champion “When I shoot limited (iron sight), I close one eye. When I shoot open (scope) I leave both eyes open. I am right-eye dominant, but even when I close my left eye, I bring the gun over to my right eye. I don’t like to move my head, because it won’t always be in the same position. It’s more consistent for me to bring the gun to my eye. I always bring the gun over to my dominant eye, but it still seems to be pretty centered. Consistency is very important when it comes to acquiring the sights at speed, and it is more consistent for me to bring the gun to my dominant eye.”
Dennis DeMille—National Service and Long Range Rifle Champion “I close my non-shooting eye initially. Once I pick up my sight picture it’s not something I focus on. For those that use a patch, I recommend that they use something white to block their view rather than cover the eye. The eyes are made to work together, so if you put an eye patch over your non-shooting eye, the other eye will be affected as well. Putting a piece of scotch tape, masking tape, or even a white paster over the upper part of the lens covering the non-shooting eye works well. It only needs to obscure the line of sight to the front sight.”
Julie Golob—National Action Pistol Champion “I shoot with both eyes open. Some shooters just don’t see well with both eyes open though and can even see two sight pictures. In that case I encourage them to either use a piece of frosted tape to cover the line of sight for one eye, or squint. I am fortunate that the gun naturally lines up to my point of aim. I am right handed and right-eye dominant, so it’s not much of an issue for me to line things up easily. For cross-dominant shooters that can keep both eyes open, I suggest a simple tilt of the head to line up their dominant eye with the sights.”
Phil Hemphill—National Police and Bullseye Pistol Champion “In Bullseye I use a patch over my non-dominant eye, which helps with muscle fatigue. I have tried closing my left eye using the eye muscles and I tend to get some eye fatigue from doing so. “Eye patches are not legal in PPC (Police Pistol Competition), so I squint my left eye, trying to avoid the muscle fatigue again. This also helps me to ‘clear’
Bruce Piatt—NRA World Shooting Champion, National, Bullseye and Action Pistol Champion “Depending on the type of shooting, I will place a piece of translucent scotch tape over the upper half of the glasses on my non-dominant eye. I do this for Bullseye and almost all iron sight NRA Action Pistol events. When shooting events that are fast paced, I want the non-dominant eye to help locate the next target. On all aerial shotgun events, I will have both eyes open. I hold the pistol directly in front of my face, not for visual reasons but to balance the recoil of the pistol. Having the pistol to one side or the other will change the amount of recoil traveling up each arm, causing the pistol to track unevenly during recoil and, most importantly, during sight acquisition for the next shot. The faster the shooting, the more important a balanced stance is.
“Some shooters, especially those with nearly equal or cross dominance, will naturally find themselves squinting one eye. When anyone does this, you are also closing your dominant eye to some extent and adding stress to your face. Being relaxed as much as you can will lead to proper shooting. Keeping your dominant eye open during the entire firing sequence (during the wobble stage, pressing the trigger, the gun’s recoil and the return of the sight or follow thru) will lead to ‘reading the sight’ and learning from each shot fired.”
Carroll Pilant—Marketing Manager, Sierra Bullets and Action Pistol Champion “I am right handed and left eye dominant, so I close my right eye and roll my head slightly right so that my left eye is centered up with the pistol and the pistol is still centered up with my body. A few of my handguns have the old style Holosights on them and I actually shoot them with both eyes open. That is about the only dot sighting device I can shoot with both eyes open though. With iron sights, I always use my dominant left eye. When shooting strong hand only, I still center the handgun with my body and roll my head slightly right and use my dominant left eye again. When shooting a rifle with iron sights, I am fortunate enough that I can shoot a rifle as well left handed as I can right handed, so I just shoot iron sighted rifles left handed.”
Judy Tant—National Bullseye Pistol Champion “I shoot with both eyes open. I shoot right handed but am left eye dominant. Fortunately, my right eye is strong enough (with corrections) to see the target adequately dominating (which for bullseye is not a high standard), so I occlude my left eye with a small tab of translucent tape that blocks sight of the target only when I am in my usual stance. This leaves a lot of my left lens uncovered so that I can see reasonably well out of it when scoring. I like translucent tape rather than something more opaque because it minimizes the disparity in light reaching the two eyes, which is desirable I am told. Shooting left eyed would be very uncomfortable for my neck, though I know of shooters who manage with this arrangement. When I first started out, I blocked the left eye completely, but that was a nuisance because it left me either half blind or needing to fiddle with flip-up patches or separate glasses for going down range to score. And before that, I think I just closed my left eye, an obvious inferior approach that I would advise against.”
David Tubb—National Service and Long Range Rifle Champion “I keep both eyes open, always. Some use an opaque blinder in rifle or shotgun shooting. If you close your non-dominant eye, you will not get as good a sight picture—to say nothing of the extra time involved (closing gives sympathetic enlargement of pupil). If your aiming eye is not your dominant eye, you have even more of a problem to overcome. I cannot recall there ever being a national champion rifle or shotgun shooter with a non-dominant aiming eye.”
Lones Wigger—World, National and Olympic Champion Rifleman “I don’t shoot high power rifle anymore but the technique for iron sights is the same for all rifle disciplines that utilize an adjustable rear aperture to control the amount of light into the shooting eye. Iron sight shooters with such a sight, focus on the entire sight picture—not just the front sight or target. Pistol and service rifle shooters, however, focus on the front sight which is a different technique since they can’t control the amount of light allowed into the shooting eye through the sight unless they are using a scope. All shooters should use their dominate eye to look at the sights. Even then, the non-dominant eye will sometimes take over. If this forces you to squint, use a blinder attached to the sight or a blocker on the lens of the non-shooting eye so it will not take over. This problem is more apparent when you use the non-dominant eye. As a rule of thumb, shooters should try to use the dominant eye unless the vision is impaired and the non-dominant eye has better vision. You should always shoot with both eyes open since this will allow the shooting eye to function properly.”