Ocular dominance often shifts in the horizontal field

JoeW

AzB Silver Member
Silver Member
Kahn, AZ and Crawford, JD. (2001). Ocular dominance reverses as a function of horizontal gaze angle. PubMed.
In a reach-grasp task for targets within the binocular visual field, subjects switched between left and right eye dominance depending on horizontal gaze angle. On average, ocular dominance switched at gaze angles of only 15.5 degrees off center.http://www.ncbi.nlm.nih.gov/pubmed/11369037?dopt=Abstract

Quartley, J and Firth, AY (2004). Binocular sighting ocular dominance changes with different angles of horizontal gaze. PubMed.
A change in eye dominance occurs when viewing in the contralateral field. Differences may exist in the angle at which this occurs due to the different conditions of the various tests for ocular dominance. http://www.ncbi.nlm.nih.gov/pubmed/14998366?dopt=Abstract

The research summarized above indicates that eye dominance can and does change as one moves into a pool shot from across the horizontal field. For some people when they move into the shot making position from the left or from the right their eye dominance shifts as they look at the sighting point.

The obvious solution to this shift in dominance is to walk into the shot from behind. While you may be looking at the shot from the side as you walk to it, you probably should not begin to sight the shot until you are in position and take a step back. This will place you on the shot line, yield a better perspective, and will give your eyes and their dominance preferences time to adjust to the visual field directly in front of you. This type of recommendation has been around for a long time and is now reinforced by the research literature.

Whether you choose to place the cue under the dominant eye or allow the brain to compensate for the dominant eye is another choice. The research literature seems to imply that shift in dominance in the lateral and contra-lateral field is not an invariant process across people: Some people experience more of a shift than others. If you have noted this shift in dominance and or a change in dominance then it is probably more important for you to step back when on the shot line and look directly in front of you prior to sighting.

A more extensive literature review on this topic would probably yield even stronger evidence as we are dealing with a physiological process offset by mental preferences. Pool instructors should seriously review this literature and it probably should be a standard recommendation based on solid research findings. While some people may not have a lateral shift in dominance the recommendation to take a step back allows one to gain a better perspective.
 
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The Renfro

Outsville.com
Silver Member
Thanks Joe!!! Now maybe the people that think it's not important can understand for some of us it is =)
 

One Pocket John

AzB Silver Member
Silver Member
Just read

http://www.sharp-sighted.org/index.php?option=com_content&task=view&id=82&Itemid=149

I am right handed and right eye dominent.

I performed the "Miles Test" using a CD on my pool table looking at a ball at
about 18" away and then a ball at about 8' away.

What I noticed was on the closer ball as I brought the CD closer to my head was that the hole came right into my right eye. When I used the CD on the ball that was 8' away and brought the CD closer to my head the hole ended up closer to the bridge of my nose.

I gotta do some more testing on this. In fact I think I'll do the test in the shooting position to see what happens.

Thanks for the thread Joe

John
 

ENGLISH!

Banned
Silver Member
John,

I just did the test & since I was on-line I did it with my reading glasses on. The glasses are the weakest .25 'dollar store' type so I can still see welll with them at some distance. I was shocked that the close up object results were similiar to yours. Then I 'real eyesed' that I had my glasses on. So, I did it again without them several times & I am right eyed. The reading glasses thing was interesting though.

Regards,
 
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JoeW

AzB Silver Member
Silver Member
The development of the visual grid and the origin of ocular dominance indicates that there are horizontal and vertical dimensions to ocular dominance.

http://www.sharp-sighted.org/index.php?option=com_content&task=view&id=39&Itemid=93

I have not found a study that address the shift in ocular dominace along the vertical axis. Most of these studies are more concerned with the topographical brain mapping and ontological development. However. it would tentatively appear that ocular dominance can shift along the vertical axis.

This may lead to the idea that dominance can also shift as one moves from the standing position to the bent over position. Maybe, maybe not. At any rate it would be good to in some way determine if the sight picture is different with regard to ocular dominance from these two positions.

My personal preference has been to continuously stare at the target while bending over. I know the perspective changes and have thought the brain developed a "better" sight picture if one watched the target while bending over. When the target is fixed in my visual field then I go into the rest of the pre-shot routine.

Now I wonder if there is any sort of shift in dominance from one position to the other. The stereotaxic figures in the article referenced shows that visual representations are variously located for the vertical plane.

With different physical locations I would expect the development of different patterns of representation.

And of course, this supports my opinion that one should watch the target as they bend over for any changes in perspective and to account for the parallax problem.

I used the Miles test while bending over and saw what appears to be slight shift in ocular dominance. I can't rule out confirmatory bias so it may or may not be true. An "n" of one is simply not sufficient. If true it implies that sighting may be different from the standing position than it is from the shooting position.
 
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JoeW

AzB Silver Member
Silver Member
And of course all these studies confirms my initial position that the brain "knows" how to adapt to ocular dominance. In my thinking it is best to pick a reference point, such as the center of the chin, and let the brain take care of the rest. Stepping into the shot line and continuously staring at the target while bending over only facilitate the brain's natural abilities.

Your milage will definitely vary.;)
 

JoeW

AzB Silver Member
Silver Member
Just read

http://www.sharp-sighted.org/index.php?option=com_content&task=view&id=82&Itemid=149

I am right handed and right eye dominent.

I performed the "Miles Test" using a CD on my pool table looking at a ball at
about 18" away and then a ball at about 8' away.

What I noticed was on the closer ball as I brought the CD closer to my head was that the hole came right into my right eye. When I used the CD on the ball that was 8' away and brought the CD closer to my head the hole ended up closer to the bridge of my nose.

I gotta do some more testing on this. In fact I think I'll do the test in the shooting position to see what happens.

Thanks for the thread Joe

John

Though I have not read any studies that indicate that ocular dominance shifts over various distances from the eye, it makes sense that this would happen as the perspective changes and the eyes would accommodate to this change with a change in emphasis based on eye preferences.

While visual preferences are indeed a real phenomena I think that we need to respect the brain's ability to deal with physical changes in the environment as seen from changing body positions.

For those who are curious, you can conduct a version of the "Miles Test" by over lapping your thumbs and index fingers to make a small hole. Hold your arms extended and look at some small object. Close one eye and then the other eye. With monocular vision you will see different pictures. The amount of difference will show you the preferences your individual eyes have for sighting an object.

You can try the test with objects at various distances and located at various places in the horizontal and vertical planes to see if you have any shift in ocular dominance.

Sighting an object through a CD is a better way to get a standard for comparison.
 
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chevybob20

AzB Silver Member
Silver Member
I've found that I can make my eye dominance shift with motion. Perform the Miles test but move the card with the hole rapidly into place from right to left with both eyes open, then close an eye to see which is dominate (mine will be the left eye). Repeat the test from the other direction and see what happens.
 

3andstop

Focus
Silver Member
This is all way over my head, but I can tell you there was a period in my play that really stressed my confidence level while shooting long shots with any angle other than straight in at moderate to soft speed.

When I walk into a shot I get down on it and after honing in my stroke, I focus on the object ball as I stroke the shot.

While staying down on the shot and seeing the CB into the spot on the OB that I shot at, my eyes see the shot at about the halfway point as being way off line. so much off line that I'm going to miss by a full diamond.

Then as the CB contacts the OB it is a perfect hit right on the target I aimed at.

I have learned to trust my aim prior to contacting the CB and allow myself to totally disregard this optical illusion I see on these shots.

I dunno if this is relative to your post but thought it would be of interest.
 

JoeW

AzB Silver Member
Silver Member
I use a similar procedure 3andstop. I reinvented the wheel and was later told that golfers use this trick. They call it an intermediate target and it is what I too use. On long shots I select a spot on the table about half way to the target and then try to line up the CB, intermediate target, and the contact point. When I feel that these three are lined up I make the shot effortlessly, Well only if I follow my PSR.
 

JoeW

AzB Silver Member
Silver Member
I've found that I can make my eye dominance shift with motion. Perform the Miles test but move the card with the hole rapidly into place from right to left with both eyes open, then close an eye to see which is dominate (mine will be the left eye). Repeat the test from the other direction and see what happens.

Apparently eye dominance changes in all three dimensions and with movement. This could become a very difficult topic. Reminds me of the idea that I should not run with scissors. :grin:
 

3andstop

Focus
Silver Member
I use a similar procedure 3andstop. I reinvented the wheel and was later told that golfers use this trick. They call it an intermediate target and it is what I too use. On long shots I select a spot on the table about half way to the target and then try to line up the CB, intermediate target, and the contact point. When I feel that these three are lined up I make the shot effortlessly, Well only if I follow my PSR.


Joe, I don't so much use an intermediate target, but rather have trained myself to disregard the optical illusion I see as the CB is halfway to its target.

I've learned to trust that my original aim line at the CB, prior to shooting is correct, and that has regained my confidence in pocketing the ball.

In the years past, this was one aspect of my game that mentally held me back as I was unsure I was online initially. Now, I realize that what I see when the CB is at its halfway point toward the OB is irrelevant and my original aim line and envisioning of the shot is accurate.

The reason I see the tracking of the CB so off at the midway point, I'm assuming has to do with depth perception and eye dominance. It is just such a strange phenomenon that it took a lot of play to overcome that mental block to my shot making confidence. :)
 

chevybob20

AzB Silver Member
Silver Member
Apparently eye dominance changes in all three dimensions and with movement. This could become a very difficult topic. Reminds me of the idea that I should not run with scissors. :grin:

The solution that I've found (so far) is exactly what you said. I come in from straight be hind the shot after initial sighting while standing. I have found that if I keep the cue in my peripheral vision while standing and then watch it come in from the left while bending in for the shot helps. Also, everything I do including sighting while standing must be part of the PSR.
 

KCRack'em

I'm not argumentative!!!!
Silver Member
I'll dig into this later, but I want to put this out there first:

I was decent player before I left the game for several years. Back then my left eye wasn't very useful. It was hard to correct so I gave up trying. I had learned to compensate very well, and could throw, catch, shoot a basketball, etc. very well. I played pool pretty well considering that I wasn't a student of the game and just picked it up in bars/on campus.

Fast forward into my college years (after active duty) and a local teenager (one of the best players in the area) asked me if I was blind in my left eye. He watched me shoot and noticed that my cue was very much in line with my right eye. I didn't realize I was doing it.

Not long after college I lost interest in the game and stayed away for most of about 8 years.

Just over two years ago I had cataract surgery and now have far better vision in the left eye than I can recall at any point in my life. I wear glasses now and have some correction for both eyes. If both are fully corrected, I see double. It's called vertical imbalance. My prescription glasses are tweaked to allow my right eye to be dominant. I just had another exam a few days ago, and the vertical imbalance hasn't improved. The Doc said he uses a prism to keep it at bay. I'm not entirely sure what that means......

It was after surgery that I decided to start playing again.

I play okay, but it really is different seeing well with both eyes. I could wear bifocals, but choose instead to take my glasses off for up close work. I have prescription reading glasses, but seldom need them. I do wear my glasses to shoot pool.

I know it's a novel, but I would like to read advice/ideas about how to play to overcome this. The game was so much easier before. I don't mind that it's more of a challenge. By the way, I mentioned some other sports because I can't catch a frisbee or anything like that the way I used to. It sucks!
 

chefjeff

If not now...
Silver Member
The development of the visual grid and the origin of ocular dominance indicates that there are horizontal and vertical dimensions to ocular dominance.

http://www.sharp-sighted.org/index.php?option=com_content&task=view&id=39&Itemid=93

I have not found a study that address the shift in ocular dominace along the vertical axis. Most of these studies are more concerned with the topographical brain mapping and ontological development. However. it would tentatively appear that ocular dominance can shift along the vertical axis.

This may lead to the idea that dominance can also shift as one moves from the standing position to the bent over position. Maybe, maybe not. At any rate it would be good to in some way determine if the sight picture is different with regard to ocular dominance from these two positions.

My personal preference has been to continuously stare at the target while bending over. I know the perspective changes and have thought the brain developed a "better" sight picture if one watched the target while bending over. When the target is fixed in my visual field then I go into the rest of the pre-shot routine.

Now I wonder if there is any sort of shift in dominance from one position to the other. The stereotaxic figures in the article referenced shows that visual representations are variously located for the vertical plane.

With different physical locations I would expect the development of different patterns of representation.

And of course, this supports my opinion that one should watch the target as they bend over for any changes in perspective and to account for the parallax problem.

I used the Miles test while bending over and saw what appears to be slight shift in ocular dominance. I can't rule out confirmatory bias so it may or may not be true. An "n" of one is simply not sufficient. If true it implies that sighting may be different from the standing position than it is from the shooting position.

That's why in that other thread I recommended first seeing the aim while standing, then placing the back foot and then the front foot while still standing straight up, THEN FIRST bending the knees to drop down, THEN bending at the waist to get fully into the stance.

I've found this really helps to keep my dominant eye over the line.

Thanks for the thread and info, btw.

Jeff Livingston
 

chefjeff

If not now...
Silver Member
IS THIS HARMFUL TO ONE'S EYES?

One of those articles mentioned to "be careful" when changing eyes. I had that concern and when at my ophthalmologist's appointment last month I asked if what I was doing was harmful. The answer: "Not at all."

fwiw,

Jeff Livingston
 

chefjeff

If not now...
Silver Member
The Doc said he uses a prism to keep it at bay. I'm not entirely sure what that means......

It means one eye looks in a different direction than does the other.

I have that condition and have overcome it with my mind. It took my 6 months before I could control seeing double without my glasses. Driving home from league was a trip, to say the least! I had to do that self-correction before my doctor would do lasik.

He sent me to a specialist (I forget his title but his main thing is cross-eyed children...the waiting room was full of 'em) who was a ping pong player. This guy worked with me for 3 hours (!!!) and was very interested in my pool playing and told me that pool was probably one of the best exercises possible for my condition and without it, I'd quickly revert back to double vision.

He tested me over and over and confirmed that I had self-corrected so my ophthalmologist got the OK to do surgery on me. He also said that when I reach 65 or so, I'll lose the ability to overcome this and will probably need prism glasses (that I wore for 30 years before).

Get a good doctor who will listen and help you through the process.

I'm 59, btw, so my time is coming.:frown:

Jeff Livingston
 
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