Most people I know, at one point in their lifelong pursuit to become a better player, get obsessed with "vision center" or the "dominating eye".
So did I. But after experimenting and thinking about it, I realized that most information found on the subject are trial and error suggestions, re-told myths.
The quote below from the "stroking straight question", thread, especially the part in bold, has motivated me to write those thoughts down, in hope that this may help someone.
I do believe there is a vision center and most likely a dominant eye, but the conclusions drawn in the hope of improving one's game are often wrong. Especially, experimentation in the classical sense is not the correct way to go about it. What you see is what you get. If you need to get used to something looking wrong, chances are likely that it is wrong in the first place.
Here's my theory (and it's just that, a theory):
It starts with someone having tendencies to
a) over cut shots to one side, and under cut shots to the other side, and/or
b) unwanted side spin, predominantly towards one side of the cue ball
With only this information, the source of the problem can be stroke and/or alignment related.
Then, someone suggests that it might be because their vision center is not on the line of the shot. That might still very well be true. They are then advised to do one of those dominant eye tests.
Let's do one too, shall we. Cut a small hole through a sheet of A4 paper. Hold it at arms length. Look at a small distant object through that hole with both eyes open. Close one eye at a time. If you see the object, according to the test, this eye is your dominant eye.
If you do this test yourself, you are likely to find that one particular eye usually gets the glance at the object, while the other's view is blocked by the paper. At least for me, there's a clear tendency to catch the object with my left eye. But to draw the conclusion that one must have the cue under that eye, or at least slightly towards that eye, in order to be aligned, is nothing but guesswork. The reason why one eye wins over the other is at least as much related to the way the paper is moved (hand-eye coordination).
To understand why, now do the test differently. Move the paper from left to right, somewhat slowly, until you see the distant object. It will always be your left eye that can physically see the object first, while it is still hidden by the paper from your right eye. Then, move the paper from right to left until you see the object. You will see it with your right eye. Seeing the object with either eye doesn't pose any problems for your brain.
Once one eye has made visual contact on the object through the hole, try turning your head left- or rightwards while keeping the distant object in sight. However you rotate your head, and which ever eye you use, your brain automatically puts your "handicapped vision center" on the line between hole-in-the-paper and the distant object. It doesn't look "wrong" or "off", even with your not-so-dominating eye. It wouldn't make sense to move the "dominant" eye closer to that line. You would just not see the object anymore.
Of couse, this test cannot be done without the paper, but the conclusion I draw from this is: don't move your head purposely towards what you think is your dominant eye, especially not if you what you then see looks "off" or like you need to "get used to" it before any positive effects may kick in.
Instead, without paying any attention to where your eyes are in relation to the cue, move your head so that
a) the cue looks perfectly centered
b) looks perfectly vertical and not at an angle to the left or the right.
Like so:
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Fig. 1. Vision center on the line of the cue.
and not like
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Fig.2. Vision center to the right of, but parallel to the cue.
or
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---------//-----------
--------//------------
Fig.3. Cue angled
Pay great attention to how the cue is aligned in your vision, try to notice even small deviations. If you see the cue as in Fig.1, your own, individual, personal, unique, whatever, ... "vision center" is hovering on top of the shot line, or on the plane of the shot. Without you having to consciously hold your head in any particular fashion. That's what you want, and that's all you can ask for w.r.t. alignment with your cue. As before, you can try turning your head. For any head orientation, there will also be a position of your head where the cue looks like Fig.1.
Now introduce a cue ball and an object ball. No need for a pocket, just aim for a full hit on the object ball, with the cue tip in the vertical center of the cue ball tip (i.e. no side spin). While you get down on the shot, focus mainly on cue ball and object ball, i.e. the line of the shot. Make sure to stay on the line, so that the line between the centers of the balls is not angled and centered in your vision, just as the cue was in the previous test. Then pay attention to the cue as before. You may have to adjust both your head and your cue to get everything on line.
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Fig. 4. Balls, cue and vision center in perfect alignment.
If a full hit (a.k.a. straight in) shot doesn't look like Fig.4, then your alignment is off. Only subconscious last second swoops and quirks can make you strike along the line of the shot. If it looks like Fig.4., as far as alignment goes, you're good to go. In practice, of course, it is hard to spot small deviations from Fig.4, so small inaccuracies will still happen. But the more you focus on the alignment, the more accurate you will get, and the more you can trust (or work on) your stroke.
The bottom line is: it doesn't matter whether the cue is perfectly centered between your eyes, slightly towards or straight under one eye. Whether you stare straight at the line of the shot, or whether your head is turned. All that matter is that the output of your brain's stereo vision algorithm (i.e. what you perceive and see) is aligned and centered on the line of the shot, and that you put your cue on that line as accurately as you can. See Fig. 4.
Stephen Hendry (7 times snooker world champion) started his career playing with the cue centered on his chin, and with time the cue moved towards one eye. Asked about it, he said it just happened. While only he knows whether that's true, or whether he tinkered with it as countless others have before, letting it happen naturally is the correct way to align.
So don't randomly move your head towards one eye or the other, hoping that this will fix your problems once your brain has adapted. Instead, make sure what you see is in accordance with what you want to achieve.
And then, unfortunately for most of us, comes the much harder problem: controlling your muscles to keep the cue on that line throughout the stroke.
So did I. But after experimenting and thinking about it, I realized that most information found on the subject are trial and error suggestions, re-told myths.
The quote below from the "stroking straight question", thread, especially the part in bold, has motivated me to write those thoughts down, in hope that this may help someone.
Unknown said:Just because you feel comfortable in a certain position, doesn't mean you can stroke the cue in a straight line from there. You just have to experiment with it and if part of the solution is moving your vision one way or the other, you'll get used to it soon enough.
.
I do believe there is a vision center and most likely a dominant eye, but the conclusions drawn in the hope of improving one's game are often wrong. Especially, experimentation in the classical sense is not the correct way to go about it. What you see is what you get. If you need to get used to something looking wrong, chances are likely that it is wrong in the first place.
Here's my theory (and it's just that, a theory):
It starts with someone having tendencies to
a) over cut shots to one side, and under cut shots to the other side, and/or
b) unwanted side spin, predominantly towards one side of the cue ball
With only this information, the source of the problem can be stroke and/or alignment related.
Then, someone suggests that it might be because their vision center is not on the line of the shot. That might still very well be true. They are then advised to do one of those dominant eye tests.
Let's do one too, shall we. Cut a small hole through a sheet of A4 paper. Hold it at arms length. Look at a small distant object through that hole with both eyes open. Close one eye at a time. If you see the object, according to the test, this eye is your dominant eye.
If you do this test yourself, you are likely to find that one particular eye usually gets the glance at the object, while the other's view is blocked by the paper. At least for me, there's a clear tendency to catch the object with my left eye. But to draw the conclusion that one must have the cue under that eye, or at least slightly towards that eye, in order to be aligned, is nothing but guesswork. The reason why one eye wins over the other is at least as much related to the way the paper is moved (hand-eye coordination).
To understand why, now do the test differently. Move the paper from left to right, somewhat slowly, until you see the distant object. It will always be your left eye that can physically see the object first, while it is still hidden by the paper from your right eye. Then, move the paper from right to left until you see the object. You will see it with your right eye. Seeing the object with either eye doesn't pose any problems for your brain.
Once one eye has made visual contact on the object through the hole, try turning your head left- or rightwards while keeping the distant object in sight. However you rotate your head, and which ever eye you use, your brain automatically puts your "handicapped vision center" on the line between hole-in-the-paper and the distant object. It doesn't look "wrong" or "off", even with your not-so-dominating eye. It wouldn't make sense to move the "dominant" eye closer to that line. You would just not see the object anymore.
Of couse, this test cannot be done without the paper, but the conclusion I draw from this is: don't move your head purposely towards what you think is your dominant eye, especially not if you what you then see looks "off" or like you need to "get used to" it before any positive effects may kick in.
Instead, without paying any attention to where your eyes are in relation to the cue, move your head so that
a) the cue looks perfectly centered
b) looks perfectly vertical and not at an angle to the left or the right.
Like so:
----------||----------
----------||----------
----------||----------
Fig. 1. Vision center on the line of the cue.
and not like
------||--------------
------||--------------
------||--------------
Fig.2. Vision center to the right of, but parallel to the cue.
or
----------//----------
---------//-----------
--------//------------
Fig.3. Cue angled
Pay great attention to how the cue is aligned in your vision, try to notice even small deviations. If you see the cue as in Fig.1, your own, individual, personal, unique, whatever, ... "vision center" is hovering on top of the shot line, or on the plane of the shot. Without you having to consciously hold your head in any particular fashion. That's what you want, and that's all you can ask for w.r.t. alignment with your cue. As before, you can try turning your head. For any head orientation, there will also be a position of your head where the cue looks like Fig.1.
Now introduce a cue ball and an object ball. No need for a pocket, just aim for a full hit on the object ball, with the cue tip in the vertical center of the cue ball tip (i.e. no side spin). While you get down on the shot, focus mainly on cue ball and object ball, i.e. the line of the shot. Make sure to stay on the line, so that the line between the centers of the balls is not angled and centered in your vision, just as the cue was in the previous test. Then pay attention to the cue as before. You may have to adjust both your head and your cue to get everything on line.
----------0----------
----------------------
----------------------
----------0-----------
----------------------
----------||----------
----------||----------
----------||----------
Fig. 4. Balls, cue and vision center in perfect alignment.
If a full hit (a.k.a. straight in) shot doesn't look like Fig.4, then your alignment is off. Only subconscious last second swoops and quirks can make you strike along the line of the shot. If it looks like Fig.4., as far as alignment goes, you're good to go. In practice, of course, it is hard to spot small deviations from Fig.4, so small inaccuracies will still happen. But the more you focus on the alignment, the more accurate you will get, and the more you can trust (or work on) your stroke.
The bottom line is: it doesn't matter whether the cue is perfectly centered between your eyes, slightly towards or straight under one eye. Whether you stare straight at the line of the shot, or whether your head is turned. All that matter is that the output of your brain's stereo vision algorithm (i.e. what you perceive and see) is aligned and centered on the line of the shot, and that you put your cue on that line as accurately as you can. See Fig. 4.
Stephen Hendry (7 times snooker world champion) started his career playing with the cue centered on his chin, and with time the cue moved towards one eye. Asked about it, he said it just happened. While only he knows whether that's true, or whether he tinkered with it as countless others have before, letting it happen naturally is the correct way to align.
So don't randomly move your head towards one eye or the other, hoping that this will fix your problems once your brain has adapted. Instead, make sure what you see is in accordance with what you want to achieve.
And then, unfortunately for most of us, comes the much harder problem: controlling your muscles to keep the cue on that line throughout the stroke.
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