Dear Allan,
Eye dominance (ED) only matters if you are not aware of what it is, when it affects you, how it affects you, and what to do about it. So that's 99% of the golfers I haven't taught yet!
1. What is ED:
ED is how the brain solves the problem of accurate targeting the direct line from face to target, given that the eyes are in two separate positions in the head. The brain, when sighting this relationship, effectively blinds one eye even though it remains open. But ED differs from person to person not only in terms of severity of degree of dominance of one eye over the other, but also in terms of what alters eye dominance, and how permanent eye dominance is.
Studies show that eye dominance matters in different ways in different sports (see
Griffiths). In putting, standing behind the ball, golf is an aiming sport, but standing beside the ball it is not, and is more an anticipation of impact sport like hitting a tennis ball with a racket. When golfers try to "aim" the putter face thru the ball at a target while standing beside the ball, they do a VERY poor job. (They need to learn how to do a good job.)
In addition, different sports encourage different patterns of eye dominance. Field sports like football and cricket result in players with a lot less one-eye dominance, and more cross-dominance as well. Moving-ball sports promote less concern for eye dominance and more for anticipatory impact of the moving ball thru dynamic visual acuity and depth perception of moving objects.
Also, eye dominance is not fixed for all time, but is maleable to different degrees for different people. And eye dominance fluctuates under certain typical situations, such as when the target is on the non-dominant side, or the largest object or most threatening object is on the non-dominant side, which causes a tendency for the person's eye dominance to shift temporarily more to the non-dominant side.
2. When ED matters:
ED only matters when sighting at something, and not when casually "looking" towards something.
Sighting usually most often occurs from behind the ball when aiming down the line at the already-identified target spot in order to aim the putter face down the line when setting up.
Sighting can also occur when trying to line up the logo or line on the ball at a target, again with the face behind the ball looking down the line with two eyes.
When setting up beside the ball, eye dominance does not matter unless the golfer is still "hunting" the aim of the putter face at a target from beside the ball. he should not do this, but should instead base the aim on sighting perceptions behind the ball and then when he stands beside the ball merely "check" where in fact the putter face has been aimed. In this "checking" process, eye dominance does not matter so long as the golfer knows how to set the face and eyeline to match the putter aim, use a straight-out gaze, turn the head like an apple on a stick, and know to use the aim spot in the straight-out gaze to "see" exactly where the putter is aimed. In none of this does ED matter; it's all simple geometry and everyone sees the same line in the same way so long as their eyes are not defective.
The idea that golfers with right-eye dominance aim the putter down a different line than golfers with left-eye dominance is pure hooey. There is only one real, objective line between the ball and the target, and all golfers need the skills to see the same line from behind the ball and beside the ball. Given a single target 20 feet off, a right-eye golfer needs to aim the putter face down the same line at this target that a left-eye dominant golfer aims down. Anyone who doesn't aim down this real line needs help in how to look with good geometry.
If an untrained golfer is "hunting" for the line between the ball and the target when standing beside the ball, his eye dominance will probably influence him a little to make him see the target's location left or right of where it really is, so that is bad. The geometry of his gaze and head turn, unless correct, will play an even greater role in generated bad information about the target's real location in space.
3. How ED affects you:
From behind the ball sighting the line, the brain with two eyes open will functionally ignore the vision in one of the two eyes in order to "see" out of the face from only one location, not two. If you position the middle of the face / nose directly above what you think is the line between ball and target extended back under the middle of your stance, the likelihood is that ED will aim the dominant eye from slightly offset to the side of the line inward to the target (moreso the closer the target). This generates a sense in the body that the target is slightly to the opposite side of the line straight at it. A right ED golfer would sense the target as a bit to the left of its real location, and vice versa. Dave Stockton Jr. is the only person in golf to advise golfers to center their dominant eye directly above the line from ball to target when standing behind the ball sighting the real line from ball to target.
From beside the ball, when a golfer ill-advisedly "hunts" for the relationship between ball and target, he first looks down at the ball and then "turns" in some fashion his head and eyes targetward and ends up "looking" at the target in some combination of neck and head posture and eyeball gaze direction.
A1. For a right ED golfer, this usually works this way: looking down at the ball in a "normal" slightly left-of-center ball position, the right eye aims at it by adjusting the gaze slightly and leaving the face possibly also aiming at the ball or flush to the ground aiming at a spot behind the ball, so the right eye gaze is not straight out of the face but angled inwards towards the nose a bit. Nowadays (not in the 1960s), golfers ALSO angle their eyeballs down their cheeks as in reading a book. So the eyeball aims downward and inward. Beginning with this eyeball-gaze-to-face relationship with the eyeball aimed inward-at-the-nose and down the cheek, the untrained golfer than just sort of turns the head and face in any old way targetward. The head-gaze relation will direct the line of sight on the ground curling inside off the real line. The usual untrained head turn "lifts" the face chin-inward-at-shoulder, which further runs the line of sight to the inside. Once this curling inwards starts, in order to actually "look at" the real target, the golfer has to redirect his gaze and/or his face aim to get his line of sight back at the target. At the end, the golfer's right eye aims less inward and more up out of the skull and the neck-head-face-shoulders aim to the inside. This golfer will sense a conflict about where the target seems to be and where the stroke needs to go. Depending on how good and consistent the golfer is about sorting this conflict, he will usually favor the eye and miss to the outside and sometimes favor the body and miss to the inside. Sorting out this problem requires a different sorting for different length putts as well.
A2. For a left ED golfer, the above gaze-head turn pattern usually works this way: the ball in the middle of the stance forces the golfer to aim his left eyeball in towards the nose a bit, either with the face remaining flush to the surface or also turning back left a bit. Peering down the face at setup also directs the eyeball gaze down the cheek. Then the head turn does the usual thing and sends the face off to the inside of the target, forcing the golfer to redirect the eyeball more left / inward towards the nose and higher in order to "look" at the target. The right-eye gaze shift will typically travel farther and higher than a left-eye gaze shift, since the left eye is closer to the target for a right-hander. This means the conflict in targeting information between body and eyes is less severe for a left ED golfer putting right handed than it is for a right ED golfer putting right handed. So there is a slight advantage for untrained golfers who are cross-dominant for handedness and eyes. These golfers when favoring the eye over the body will also miss to the outside, but probably less severely than right ED golfer, but they will also miss to the inside occasionally when favoring the body, again probably not as severely.
B1. A step slightly up the evolutionary chain has golfers NOT changing whatever gaze direction they start with when turning the face to the target, but unfortunately they always these days start with the gaze angled down the cheeks like reading a book when first "looking" at the ball. Using this gaze pattern, but not changing it during the head turn towards the target, a right ED golfer starts with the gaze slightly inward at the nose and also down the cheek. Then as the head turns, this head-gaze combination sends the line of sight curving desperately off the the real line to the inside like a search light at Stalag 17 sweeping around the camp for escape attempts. Golfers never notice this either. As the line of sight runs off line to the inside, the golfer who does not redirect his eyeballs (it is not comfortable or normal to aim the eyeballs very high out of the face, as would be required to redirect the gaze back to the target) must necessarily shift his head and neck so the top of his head shifts back away from the ball (to the right). This head shift redirects the line of sight onto the target, but with this result: neck, head and shoulder aimed to the outside of the target's real location with gaze inward to the nose and down the cheeks but the line of sight aimed straight at the target. This golfer's body perceives the target to the outside / right of its true location and the eyes don't know this. Only a "pull" stroke will actually roll the ball at the target's real location, and many golfers like this miss to the outside most of the time.
B2. For a left ED golfer not altering his gaze during the head turn, the gaze is also misdirected curling to the inside and a neck-head-shoulders shift to the outside brings the line of sight back at the real target. Again, the degree of correction in the neck-head-shoulders is slightly less for a cross-dominant golfer, so the typical misses are a little less severely off line.
4. What to Do About ED:
Behind the ball: Align the dominant eye over the line from ball to target and sight with the dominant eye. Or, close one eye. If you close either eye, then eye dominance is eliminated entirely (close the non-dominant eye). Or, use the edge of the putter shaft as a visual ruler to connect the dots between ball and target, and use one eye to see the exact real straight line along the ground that this edge identifies, the same line that every golfer will also see using this technique. (If you keep both eyes open focusing on the ground, the shaft will appear in a confusing double image, so don't.)
Beside the Ball:
Bandaid approach for "Hunting" for the Line: The bandaid approach is to shift ball position in the setup to accommodate what bad pattern of gaze-head turn a specific golfer usually uses. Confusingly, sometimes the instructor will try to fix the setup, and sometimes the stroke. To accommodate right ED in the setup, some instructors move the ball BACK to sit beneath the right eye at address. This promotes a push stroke to the outside. Other instructors notice that the right ED golfer usually misses to the outside, so they reposition the ball FORWARD to promote a corrective pull. If the objective is to HELP the right ED golfer run his eye sight straight down the REAL line and to perceive the target location accurately, neither of these bandaids do anything helpful. It simply moves the starting position of the bad movement targetward, either back or forward. the bad gaze geometry and the bad head turn pattern remains problematic, since that didn't get corrected. Moving the ball back promotes a push, but what effect does it have on seeing the target location accurately? In A1 above, the ball position adjustment simply starts the gaze less in at the nose, but still down the cheek the same as ever, and at the end of the head turn, the gaze is still redirected more up but slightly more so and there is another tendency to direct the gaze more to the left noseward than before. So this ball position shift makes matters a little worse than before in terms of the conflict in the visual and the body sense of target location and what sort of stroke will work. Moving the ball forward in the stance promotes a pull to the inside, but what effect does it have on seeing the target location accurately? The starting gaze aims more to the nose but the same degree down the cheeks, and at the end of the head turn the gaze shifts up perhaps not as much as usual, so this mitigates the gaze-head turn problem slightly without curing it.
The same considerations apply to the left ED golfer for moving the ball back or forward in the stance, with a little less shifting and conflict due to the fact that the left eye is closer to the target to start with and the head turn is not as great, so the problem is not as severe. But nothing really gets cured.
Therapy: Partially effective help can be gained by strenthening the performance of the non-dominant eye by putting with the dominant eye closed or patched and by putting opposite handed.
Cure: Don't hunt for the line beside the ball, and instead only "check" the aim of the putter face with good head-gaze geometry. Aim the gaze of both eyes straight out of the face and not down the cheeks, set the throat line to match the leading edge and aim of the putter face, turn the head like an apple on a stick without shifting the top of the head out of position as it turns, and use the fixed gaze to look at where the putter face actually points. You can also do this with only the rear-side eye open, as this makes available the "arrow" of the skull's eye orbit where the eyebrow bone meets the nose at a peak and the head turn runs this arrow point in a straight line so that whatever this arrow ends up pointing at when the head turn concludes is where the putter face actually aims. Again, since one eye is closed, there is no eye dominance, and only the geometry matters, exactly the same for all golfers.
The bottom line is that eye dominance is only a problem if the golfer is not correctly trained in a way that eliminates the problem. For a trained golfer, there is no eye dominance problem. For everyone else, there are confusing bandaids that mask the real cure and don't fix the problem.
Cheers!
Geoff Mangum
Putting Coach and Theorist
PuttingZone.com
Golf's most advanced and comprehensive putting instruction -- you're either in the PuttingZone or not.