New player -- cross eye dominant

Siz said:
In short, I am sure that it is and advantage, but I am not 100% why. I have some ideas though.

I was looking into this some years ago, but never actually finished my research and wrote up my findings. I now have more time on my hands and am considering picking this up again. But from memory (and I need to look up my notes and references etc) the thought process is this:
  • Published research indicates that ipsi-lateral dominance is the most common type in the population as a whole

  • However, from my inspection of videos of expert snooker players, it is clear to me that contra-lateral dominance is far more common (there are plenty of videos of top players in which you can see the position of the eyes in relation to the cue when playing a shot)

  • There are two explanations for this discrepancy. One is that playing as much snooker as the pro's do has the effect of shifting the vision center away from the dominant hand. I find this so implausible that I have not considered it further. The only other explanation I can come up with is that contra-lateral dominance conveys a significant competitive advantage to the billiard player.
It remains to be shown why this should be the case. The theory that I was working on some years ago can be outlined as follows:
  1. I think that there is broad consensus that it is important for a billiards player's vision center to be above the shot line (qv for example Dr Dave's publications)

  2. There is academic research showing that an individual's eye dominance is not fixed; there are a number of factors that change it temporarily. one of these factors is an object moving laterally across the visual field. This can either be where the individual is still and an external object moves, or where the environment is still and the individual moves somewhat sideways in relation to it.

  3. The research shows further that the amount of this shift is greater when the object comes from the non-dominant side (or equivalently, where the individual's head moves towards the non-dominant side)

  4. I believe that any temporary shift in a billiards player's vision center in the course of making a shot is likely to have a significant adverse affect on performance: if the shot 'looks wrong' coming up to the point the trigger is pulled, this will manifest in any number of nasties, as the player subconsciously tries to adjust (eg steering the cue off line, snatching, letting the cue go too early, tightening the grip, moving the head/body on the shot etc)

  5. I identified two movements that can result in this sort of performance destroying temporary vision center shift. One can occur as the player walks into the shot. This is fairly easy to manage, so I won't consider it further here.
  6. The other distracting motion occurs as the cue stick is brought onto the shot line. Here, the cue is swung in across the player's visual field from direction of the non-dominant hand. If this is also the side of the player's non-dominant eye, then the shift is big and you have a problem. But if instead the cue comes in from the side the player's dominant eye is on, then the effect is not as great (see 3. above). In other words, players with contra-lateral dominance would be expected to be less severely impacted by this problem than those with ipsi-lateral dominance.

  7. There are ways of managing the problem in 6. above (and something that I am currently interested in). But it seems likely that when learning the game, those with ipsi-lateral dominance are more likely to fall by the wayside, and those with contra-lateral dominance stand a greater chance of rising to the top.
For various reasons my research involved snooker players. However I should think that similar results would apply to other cue sports (although there are differences that could conceivably be material in terms of stance and table dimensions).

Happy to receive your thoughts.
Click to expand...
Thanks for your response and for putting it in a format that's entirely readable. I think the problem with researching eye dominance --- and I've come across it myself, causing confusion, until I was able to get clarification ---- is that there are two types --- one caused by genetics and the person's anatomy and another type that can be the result of a person's eye pathology, as well as other factors not related to their anatomy.

The first type --- which for lack of a better term, I call physical eye dominance, has to do with the anatomy of the person and the way the nerves extend from each eye to the brain. Usually, one eye's configuration is more efficient than the other, causing the eye dominance. The severity of the eye dominance has to do with the scale of the difference between the two. With this type, your visually worse eye can still be your dominant eye. That won't change unless that person's nerve structure to the brain changes, and I've not heard of that changing.

The second is is the type which can change. This type can be affected by a person's eye pathology and other things, such as loss of an eye. For some reason, research doesn't seem to differentiate between the two, even though they are entirely different.

I find research to be frustrating because of this lack of clarity. When they talk about changing eye dominance, they're referring to the second type that is temporary and can change again. The first type has the strongest influence on the person. Eventually, the eye dominance wants to revert back to the physical dominance.
 
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Siz said:
In short, I am sure that it is and advantage, but I am not 100% why. I have some ideas though.

I was looking into this some years ago, but never actually finished my research and wrote up my findings. I now have more time on my hands and am considering picking this up again. But from memory (and I need to look up my notes and references etc) the thought process is this:
  • Published research indicates that ipsi-lateral dominance is the most common type in the population as a whole

  • However, from my inspection of videos of expert snooker players, it is clear to me that contra-lateral dominance is far more common (there are plenty of videos of top players in which you can see the position of the eyes in relation to the cue when playing a shot)

  • There are two explanations for this discrepancy. One is that playing as much snooker as the pro's do has the effect of shifting the vision center away from the dominant hand. I find this so implausible that I have not considered it further. The only other explanation I can come up with is that contra-lateral dominance conveys a significant competitive advantage to the billiard player.
It remains to be shown why this should be the case. The theory that I was working on some years ago can be outlined as follows:
  1. I think that there is broad consensus that it is important for a billiards player's vision center to be above the shot line (qv for example Dr Dave's publications)

  2. There is academic research showing that an individual's eye dominance is not fixed; there are a number of factors that change it temporarily. one of these factors is an object moving laterally across the visual field. This can either be where the individual is still and an external object moves, or where the environment is still and the individual moves somewhat sideways in relation to it.

  3. The research shows further that the amount of this shift is greater when the object comes from the non-dominant side (or equivalently, where the individual's head moves towards the non-dominant side)

  4. I believe that any temporary shift in a billiards player's vision center in the course of making a shot is likely to have a significant adverse affect on performance: if the shot 'looks wrong' coming up to the point the trigger is pulled, this will manifest in any number of nasties, as the player subconsciously tries to adjust (eg steering the cue off line, snatching, letting the cue go too early, tightening the grip, moving the head/body on the shot etc)

  5. I identified two movements that can result in this sort of performance destroying temporary vision center shift. One can occur as the player walks into the shot. This is fairly easy to manage, so I won't consider it further here.
  6. The other distracting motion occurs as the cue stick is brought onto the shot line. Here, the cue is swung in across the player's visual field from direction of the non-dominant hand. If this is also the side of the player's non-dominant eye, then the shift is big and you have a problem. But if instead the cue comes in from the side the player's dominant eye is on, then the effect is not as great (see 3. above). In other words, players with contra-lateral dominance would be expected to be less severely impacted by this problem than those with ipsi-lateral dominance.

  7. There are ways of managing the problem in 6. above (and something that I am currently interested in). But it seems likely that when learning the game, those with ipsi-lateral dominance are more likely to fall by the wayside, and those with contra-lateral dominance stand a greater chance of rising to the top.
For various reasons my research involved snooker players. However I should think that similar results would apply to other cue sports (although there are differences that could conceivably be material in terms of stance and table dimensions).

Happy to receive your thoughts.
Click to expand...
can you give some of these references regarding
"an individual's eye dominance is not fixed; there are a number of factors that change it temporarily one of these factors is an object moving laterally across the visual field. This can either be where the individual is still and an external object moves, or where the environment is still and the individual moves somewhat sideways in relation to it."
thanks
 
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Hi Fran. Thanks for your reply.

I hear you when you talk about lack of clarity in this area.

The two types of eye dominance that you have identified, and the lack of distinguishing between the two in the literature, seems a very good example. That particular issue is something that I was not aware of - I will let you wrestle with that one (but would be intrigued to know if you can make any progress in this area).

The particular area that I am looking at is the shift in eye dominance (or vision center) that can occur over quite a short period. I believe that it is particularly problematic because it happens when the shot is actually being played, ie between:
  • the moment the player has made up his/her mind regarding where they want to ob and cb to go and have some sort of mental image of how that is going to happen; and
  • the moment the cue comes to a halt and the ob cracks into the back of the pocket (or alternatively, the player hurls their cue across the table and starts to run out of the hall, head in hands, screaming "NOT AGAIN! WHY ME ????" before tripping up and falling on the floor crying unconsolably).
So this is a period lasting perhaps 10s to 30s. If the shift from the individual's 'neutral' vision center position starts during this period, and then drifts back, it is going to be very difficult to strike the ball confidently and therefore well.
 
bbb said:
can you give some of these references regarding
"an individual's eye dominance is not fixed; there are a number of factors that change it temporarily one of these factors is an object moving laterally across the visual field. This can either be where the individual is still and an external object moves, or where the environment is still and the individual moves somewhat sideways in relation to it."
thanks
Click to expand...
Hi. I will have to do some digging - it was almost 10 years ago that I was looking into this. But I found a couple of leads that might be helpful (or at least by a good starting point for further research).

Both these relate to firearms, and ShootingArts might have some valuable input.

There was an interesting article titled "Insight into eye dominance" from The Firearms Instructor #44. The main theme of this article is how eye dominance can be affected by a number of factors and how to develop techniques to stabilize what the authors refer to as a stable sighting plane.

There was also a clay pigeon shooting article "Sight for sore eyes" that was also interesting. The article states that the majority of the population show ipsi-lateral dominance but quotes a study showing that a much higher percentage of clay shooters were cross dominant (suggesting that the sport selects for cross dominance). In the context of 'crossers' (clays coming in from the side) the author cites a University of California study showing that eye dominance can shift when objects move across the visual field.

Regards

Siz
 
Siz
Thanks for your reply
I will send you a PM since i am not sure as a non instructor its appropriate to have this discussion here.
out of respect
I dont want to side track the thread
Fran since you are the instructor who posts the most in the forum
If you think its appropriate to continue this type of discussion here just say so
 
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bbb said:
Siz
Thanks for your reply
I will send you a PM since i am not sure as a non instructor its appropriate to have this discussion here.
out of respect
I dont want to side track the thread
Fran since you are the instructor who posts the most in the forum
If you think its appropriate to continue this type of discussion here just say so
Click to expand...
Thanks for asking but sure, absolutely continue here. It's an interesting topic and may prove helpful to someone reading it.
 
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thanks fran
siz
i did a search and found some articles mainly with rifle shooting about how to "change" your dominant eye. they had to do mainly with covering your dominant eye and forcing your non doninant eye to do the work. or with glasses smudge the lens of your dominant eye so you see better with your non dominant eye
the articles showed some success with this but noted the tendency to revert back to being cross eyed dominant
none of that i think is relevant to pool
to be continued
 
your claims of cross eye dominance being an advantage based on anecdotal observation do not prove anything since they are anecdotal
your attempt to validate your observations by refferring to articles that say
according to you
"There is academic research showing that an individual's eye dominance is not fixed; there are a number of factors that change it temporarily. one of these factors is an object moving laterally across the visual field. This can either be where the individual is still and an external object moves, or where the environment is still and the individual moves somewhat sideways in relation to it."
you then talk about the sweep from the dominant eye side being more deterimental than a sweep from the dominant eye side
i dont think that holds merit because
many players come straight down on the shot line so its not an issue
for those that do sweep
once down on the shot
at address the head is still and there is no movement across the visual field or body
the player then has his "normal" vision center and can tell if a shot is on or off
there are so many drills to train to be on line and be sure you can "see straight"
so i dont think the "momentary change" is important
to be continued
 
also
i think most players once they found their line before they go down on the shot
focus on the contact point or aim point on the object ball
they are not aligning cue ball and object ball at that stage
so the importance of vision center is diminished
 
last
even if there was some distortion of vision center in the brief time the cue stick passes in front of them
any misalignment is corrected at address when the head is still and their head is in the correct place for their vision center
(this all assumes the player has found his correct head position for his personal vision center)
jmho
your thoughts?
 
bbb said:
your thoughts?
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I am not sure that I followed all your argument - probably me being stupid. So rather than me exhibiting my stupidity in public, I will message you privately! However I will make a couple of observations that were prompted by your comments and may be of general interest.

If I understand you correctly, you say that once you are down on the shot, there is no lateral movement to upset your vision center positioning so you should be ok. That would be correct if your aiming was done after you have got into position. But legendary instructors such as Jerry Breiseth in pool or Del Hill snooker say that you should 'aim on the way in' or 'aim on the way down'. So a change to the vision center during this stage of the shot could be problematic.

You have also talked about players coming straight down on the shot line. This was something that I glossed over in my original post, but it is quite interesting. The snooker coach Nic Barrow uses video analysis that shows whether a player's head is moving from side to side as they descend into the shot or whether it is going down vertically straight. Elite players all go down straight, as if their nose is following a plumb line. However non-experts do not - they weave a little.

The weaving motion of non-experts, where the head moves from side to side, is a natural consequence of bipedal movement. When you walk, you shift your balance away from the leg that you want to move forward and towards the leg that is planted. Part of this balance shifting is accomplished by moving your head. Then you then move the other leg, and your head moves the other way. So if a novice player walks into the shot naturally, their head will move from side to side rather than going straight down. This is something that you can check for yourself quite easily, filming yourself head-on and using something like Kinovea software to process the video.

What I think is interesting is the fact that elite players tend not to walk into the shot 'naturally' with the bobbing motion that would entail; instead they have subconsciously learnt some contrived way of moving into the shot that allows them to keep their balance, and hence head, central. This is not taught (at least I have never heard anyone talk about it); rather it is something that experts learn to do by playing - as CJ Wiley is fond of saying, 'the game is the teacher'. The solutions players subconsciously develop vary. Some start with their feet together and then shuffle then quickly (O'Sullivan is a good example of this). Others have developed a slightly odd forward motion with both legs are quite bent.

This begs the question: why do elite players' heads go straight down to the shot when the natural way would be for them to sway (slightly) from side to side? My theory is that this is to prevent vision center shift, thus enabling them to aim better on the way down. However I would be interested to hear any other possible explanations.
 
Siz said:
I am not sure that I followed all your argument - probably me being stupid. So rather than me exhibiting my stupidity in public, I will message you privately! However I will make a couple of observations that were prompted by your comments and may be of general interest.

If I understand you correctly, you say that once you are down on the shot, there is no lateral movement to upset your vision center positioning so you should be ok. That would be correct if your aiming was done after you have got into position. But legendary instructors such as Jerry Breiseth in pool or Del Hill snooker say that you should 'aim on the way in' or 'aim on the way down'. So a change to the vision center during this stage of the shot could be problematic.

You have also talked about players coming straight down on the shot line. This was something that I glossed over in my original post, but it is quite interesting. The snooker coach Nic Barrow uses video analysis that shows whether a player's head is moving from side to side as they descend into the shot or whether it is going down vertically straight. Elite players all go down straight, as if their nose is following a plumb line. However non-experts do not - they weave a little.

The weaving motion of non-experts, where the head moves from side to side, is a natural consequence of bipedal movement. When you walk, you shift your balance away from the leg that you want to move forward and towards the leg that is planted. Part of this balance shifting is accomplished by moving your head. Then you then move the other leg, and your head moves the other way. So if a novice player walks into the shot naturally, their head will move from side to side rather than going straight down. This is something that you can check for yourself quite easily, filming yourself head-on and using something like Kinovea software to process the video.

What I think is interesting is the fact that elite players tend not to walk into the shot 'naturally' with the bobbing motion that would entail; instead they have subconsciously learnt some contrived way of moving into the shot that allows them to keep their balance, and hence head, central. This is not taught (at least I have never heard anyone talk about it); rather it is something that experts learn to do by playing - as CJ Wiley is fond of saying, 'the game is the teacher'. The solutions players subconsciously develop vary. Some start with their feet together and then shuffle then quickly (O'Sullivan is a good example of this). Others have developed a slightly odd forward motion with both legs are quite bent.

This begs the question: why do elite players' heads go straight down to the shot when the natural way would be for them to sway (slightly) from side to side? My theory is that this is to prevent vision center shift, thus enabling them to aim better on the way down. However I would be interested to hear any other possible explanations.
Click to expand...
i think your last paragraph should be in a new thread as it is off topic for the op
i will make some brief replies to what i have bolded but i look forward to discuss more via PM
i may not always agree with you but you bring a refreshing point of view and you have a brain.... (y)
in paragraph 2 i would have go back and review their statements in context but i think it is taught by most you aim standing up behind the table and micro adjust when down on the shot....not to aim while going down
i have seen that video from nic barrow (a long time ago) but you made me go and re view it
briefly elite players keep their head on the shot line
because when your head goes left and right
the angle from your head to the contact point changes not your vision center
if you start another thread or pm me we can discuss it further
another point nic mentioned was about "tipping" the shoulder
that will a discussion for a pm
jmho
 
My opinion is that physical eye dominance should always have priority. It's like being left or right-handed. You can train someone or yourself to switch, but they will work harder and tire sooner. The concept of eye dominance that changes --- is unreliable, in my opinion. If it had meaning to athletes, then they would constantly be adjusting the way they see their targets, which they don't. Of course, it's necessary to make an adjustment in certain situations, such as when someone's dominant eye is nearly blind, for example. They won't be able to switch their dominant eye, but they can still train themselves to pay attention to what their recessive eye sees.
 
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FranCrimi said:
My opinion is that physical eye dominance should always have priority. It's like being left or right-handed. You can train someone or yourself to switch, but they will work harder and tire sooner. The concept of eye dominance that changes --- is unreliable, in my opinion. If it had meaning to athletes, then they would constantly be adjusting the way they see their targets, which they don't. Of course, it's necessary to make an adjustment in certain situations, such as when someone's dominant eye is nearly blind, for example. They won't be able to switch their dominant eye, but they can still train themselves to pay attention to what their recessive eye sees.
Click to expand...
fran i agree with you
regarding its hard to fight mother nature or said another way natural tendencies
 
Bob Jewett said:
This guy was left-eye dominant and (mostly) right handed. He played OK and looked OK at the table. You might want to start with his stance. Go in 18 minutes for a good overhead view. The video is available but you have to watch it on YouTube.

Click to expand...
I think I've heard of him.
 
FranCrimi said:
How is it an advantage?
Click to expand...
I won't go so far as to say it's and advantage but, being right handed/left eye dominant does have the upside of being much easier to shoot left handed. I shoot right handed and have learned to adopt a more closed stance, rotating my shoulders and body to the right, bringing my head over the cue better but necessitating a slight shift in my upper arm. I've done this enough that I have mitigated the ergonomic disadvantages, and for shots that don't require contorting the body, I feel that I should be able to achieve parity with someone with another vision center. When I switch to left handed shooting, I don't have the same coordination in my arm, my stance does not naturally settle on line, et cetera. Because my vision center is more easy placed over the cue, my left hand shot basically has one thing going for it. I can overcome the disadvantage on my right side and it gives a bit of advantage on my left side.

The disadvantage is I don't practice with the mechanical bridge.
 
tomatoshooter said:
I won't go so far as to say it's and advantage but, being right handed/left eye dominant not cross have the upside of being much easier to shoot left handed. I shoot right handed and have learned to adopt a more closed stance, rotating my shoulders and body to the right, bringing my head over the cue better but necessitating a slight shift in my upper arm. I've done this enough that I have mitigated the ergonomic disadvantages, and for shots that don't require contorting the body, I feel that I should be able to achieve parity with someone with another vision center. When I switch to left handed shooting, I don't have the same coordination in my arm, my stance does not naturally settle on line, et cetera. Because my vision center is more easy placed over the cue, my left hand shot basically has one thing going for it. I can overcome the disadvantage on my right side and it gives a bit of advantage on my left side.

The disadvantage is I don't practice with the mechanical bridge.
Click to expand...
Playing left handed for you is not cross dominant so i am not sure it is relevant to the discussion
 
Thing is if your Cross Eyed, Left Handed, Right Eye Dominate, or visa versa.

If you practice with your differences you will get you game together after time,
 
bbb said:
fran i agree with you
regarding its hard to fight mother nature or said another way natural tendencies
Click to expand...
It would be like fighting your anatomy. Is it easier to walk facing forward or facing sideways? Athletes know this. The more you go against your anatomy, the harder you have to work, plus there are always consequences, like injuries, for example.
 
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