Tennis is a sport where the non-dominant eye can be quite troublesome if you don’t manage it well.
If you’re not familiar with eye dominance and how it can affect your tennis performance, especially ball judgment and timing, then read on.
You’ll learn two practical tips that help you minimize the effect of the non-dominant eye and allow you to perceive and judge the incoming ball well.
Non-Dominant Eye And Sports
A non-dominant eye does not see worse in terms of diopter, meaning you don’t have myopia in the eye, it simply means that the signal that goes through the optic nerve into the brain from the non-dominant eye travels around 15-21 milliseconds slower than from the dominant eye.
While those 20 milliseconds slower visual input make no difference in our daily life that’s not the case when it comes to sports where accurate ball tracking is the key to timing the stroke.
This is how much distance a slow ball travels in 20 milliseconds.
If you then consider that we have around 50 cm (20 inches) of the ideal zone if hitting the ball where we’re not too late and not too early, then that translates to around 50 milliseconds of time.
The ideal contact zone is around 50 milliseconds (0.05 seconds).
Now you can see how being off by 20 milliseconds can be quite detrimental to your timing when playing tennis.
And those 20 milliseconds can easily happen if your non-dominant eye is positioned in such a way that it has become the dominant one to judge the ball.
Practical Tips For Better Ball Perception
There are two ways you can minimize the negative effect of the non-dominant eye in the game of tennis.
The first one has to do with seeing the ball well in the first flight, meaning from your opponent to the bounce, and the second one has to do with seeing the ball well in the second flight, meaning from the bounce to your racket.
a) Optimal Depth Perception In The First Flight
When the ball leaves the opponent’s racket we start tracking it and judging its speed, height and direction so that we can predict where the ball is going to end up so that we can position early and prepare our stroke in time.
This first flight of the ball is very often neglected in terms of paying attention to the ball.
The key to depth perception (3D vision) is that both eyes are pointed straight towards the ball. That’s how we get stereoscopic vision which allows us to judge distance to an object really well.
What we need to do in the game of tennis when it comes to most strokes is that we need to turn our body in order to start loading up energy which we will then release into the ball to hit it with power.
My head is oriented forward on the forehand whereas on the backhand side it already started to turn to the side which is not what we want.
What tends to happen is that as we turn our body around 90 degrees to the side, our head wants to follow and also turn somewhat to the side.
But as the head turns to the side we can lose 3D depth perception.
If we happen to turn our head in such a way that our non-dominant eye is positioned more “behind” the line of sight towards the ball, then that eye is now tasked with being the dominant eye for judging the ball.
And that’s when the already existing problem of poor depth perception is exacerbated by our non-dominant eye being tasked with ball judgment.
On the forehand side my head barely turned to the side - so I have perfect ball tracking ability.
So one of the most practical tips you can do to eliminate both these problems is to make sure your head is really oriented forward towards the ball as it’s in its first flight.
Realize that there is no point in having the head slightly to the side yet as the ball is still far away when we begin stroke preparation.
The ball is in most cases well in front of us with a very small angle from our head to the ball.
Only as the ball comes really close to us (within a few feet) we actually need to turn the head and eyes to the side in order to track it well.
While the head angle difference may seem small, it can cause you to judge the ball poorly.
In my case I happen to turn my head more to the side on the backhand side and that unfortunately exposes my left non-dominant eye to the task of judging the ball and therefore I happen to misjudge the ball here and there.
It doesn’t bother me now since I am not playing competitively any more.
When I became aware of this issue many years ago I corrected it quite well by practicing keeping my head oriented really straight forward in the first flight of the ball and that helped me perceive the ball really well and rarely mistiming it
Note how Wawrinka keeps his head oriented forward even though he turns his body to the side.
I highly recommend you first test yourself in front of the mirror (or record yourself from front view - place the camera at the bottom of the net and zoom in) and then practice turning the body but not the head as you repeat forehand and backhand unit turns in front of the mirror.
b) Clear Focus In The Second Flight
The second time your non-dominant eye can cause poor timing of the ball is after the bounce.
After the ball bounces your eye dominance really comes into play.
If you happen to orient your head incorrectly so that your non-dominant eye is looking at the ball better than your dominant eye, you will get slower data transfer of its position and speed in space to your brain and that will make it much more difficult to time it well.
One of the most prominent tennis coaches at the moment Patrick Muratoglou suggests different stances and head orientations towards the ball based on different eye dominances, but I don’t think that’s practical for an adult recreational tennis player who plays tennis twice a week on average.
Adult tennis players simply do not have such good skills in using different stances and they don’t have the time to specifically train head different head positions based on their eye dominance.
I recommend a more practical approach which is trying to see the ball clearly in focus after the bounce.
Most adult tennis players obviously see the ball otherwise they wouldn’t be able to hit it but they don’t pay attention to it well enough.
At this moment you need to bring the ball clearly into focus.
In other words, they don’t see the ball clearly in focus. In some cases, their eyes and brain are simply not skilled enough to track a really fast ball but in other cases, it’s simply a lack of focus.
So if you really try to see the ball clearly in focus after the bounce then in my experience your eyes and brain will naturally find the best way to orient the head toward the ball in order to accomplish the task of seeing the ball clearly.
So you don’t even have to know which of your eyes is the non-dominant one and you don’t have to think about how to position your head differently in relation to each stroke you’re hitting, you simply do your best to see the ball clearly in focus after the bounce.
You've heard a million times but I'll repeat it once more - WATCH THE BALL!
I have previously posted an article on how to practice watching the ball better which also includes a more in-depth explanation on what it means to see the ball in focus.
You will also find 15 drills to help you practice watching the ball better in both the first flight before the bounce and in the second flight after the bounce.
Summary
We all have a non-dominant eye which transfers data through the optic nerve into the brain around 20 milliseconds slower than the dominant eye.
If we happen to orient the non-dominant eye too much towards the ball in the first flight before the bounce and / or in the second flight after the bounce then we are not perceiving the ball’s speed and depth well and that will likely result in hitting it too late.
A simple way to make sure you eliminate the "dominance of the non-dominant eye" in the first flight is to make sure your head is oriented as forward as possible as then both eyes are pointed at the ball and the dominant eye will naturally take the leading role in reading the ball’s flight and judge it well.
You will likely have to practice that for several weeks or months (sorry, 5 minute solutions don’t exist in any sport or music, so don’t fall for such clickbait titles on Youtube) before you ingrain the correct head position so that you don’t have to think about it.
The second part where your non-dominant eye can trouble you is after the ball bounces. The goal is to clearly bring the ball into focus as that will naturally orient your eyes in such a way that the dominant eye will take the lead.
Use the 15 Ball Watching Drills to continuously work on your ability to see the ball clearly and to get into a good rhythm with the ball.
That will help you bring the ball into focus well after the bounce which will naturally orient your head and eyes correctly towards the ball so that your dominant eye will be the one judging the ball more.
After hours and hours of practice with my backhand I have just discovered I am most probably hitting late most of the times. I’m right eye dominant, right hand player. Thank you so much for sharing this tip.