THE IMPORTANCE OF VISION & ATHLETIC PERFORMANCE
What role does basic vision (i.e. straight ahead, "20/20" visual acuity) have in the success of an athlete in a ball sport? Are there some sports that have a higher priority here?
Visual acuity is the foundation of your vision, it is important in all sports. However, it is much more critical in sports where the athlete is tasked with hitting a small object moving at a high rate of speed such as Baseball, Softball, and Tennis. Athletes that have poor visual acuity in one or both eyes typically don’t make it to the upper levels of their sport.
A study published in the American Journal of Ophthalmology titled -The Visual Function of Professional Baseball Players-Daniel Laby MD helps shed a little light on this subject. The study concluded that 77% of major league baseball players had greater than 20/15 visual acuity and 42% had better than 20/12.5
To help you understand what these numbers actually mean let me give you a quick example. 20/20 vision has been the standard that most people have been tested to over the years. If someone with 20/20 vision is presented with a letter on the 20/10 row on the eye chart they would have to get up and walk 10 feet closer to the chart to see the letter. Someone with 20/10 vision can see that same letter from 20 feet away. So, basically, someone with 20/10 vision sees everything 10 feet sooner than someone with 20/20 vision. Imagine how much of an advantage that is when trying to hit a pitch that is going 95 mph.
Now, all of these numbers are considered static visual acuity, which basically means, reading a target that is standing still. Dynamic visual acuity is actually much more important. This is testing the ability to see a small moving object clearly, like seeing the seams on a pitch. Dynamic visual acuity is often not tested during a routine exam, but almost all athletes should have this test done.
Although having extremely sharp visual acuity is not as important in sports such as Basketball, Football, Golf, or Soccer, it is still important to have good visual acuity. Most of these sports require excellent depth perception to be able to catch a pass, shoot a ball, or read a putt. Depth perception is the ability to judge the distance of objects in relation to yourself or another object such as a basketball goal. If you have good visual acuity in one eye and poor visual acuity in the other eye, you will have poor depth perception because both eyes are not working together.
To wrap this question up, let me give you a few more examples of how acuity can affect any given sport. An athlete that is nearsighted (can’t see far away) will always miss shots short, swing late, and will always grasp a catch too late and drop the ball. An athlete that is far-sighted will always be long on shots, swing too soon and overthrow his receiver.
So as you can see, visual acuity is very important. If you don’t get anything else out of this article, get your eyes checked and make sure you can see at least 20/20 in each eye. This can make a huge difference in your performance.
How much can this aspect of vision be improved, and if an athlete doesn't have natural 20/20 or better to the point where it is demanded by the sport, can they still reach an elite level?
There are a lot of factors that determine someone’s ability to see better than 20/20. Visual acuity starts to develop as soon as you are born. If something gets in the way of the development of one of your eyes your are less likely to develop better than 20/20 vision. For example, someone that is born with a crossed eye, or an eye that has a higher prescription than the other eye they can develop what is called amblyopia (lazy eye) if these conditions go uncorrected. Amblyopia can be corrected later in life, but it is much easier to fix at an early age than to try to catch up later in life.
One thing that many people don’t consider as an important factor to vision is good nutrition. Poor nutrition depletes the eye of nutrients called carotenoids which are highly concentrated in the macula. The macula is the part of the eye that sees the sharpest, and if it is deficient in nutrients it will not see as well as it should. Leafy green vegetables, carrots, sweet potatoes and berries are great for your eyes. There are also vision supplements available that are highly concentrated in these nutrients that can protect your eyes from oxidative stress and improve vision.
Lastly, and this may be an unpopular opinion, but too much screen time is bad for your eyes. Spending a lot of time in front of a screen can cause a lot of eye problems. One of those problems is dry eye. We typically don’t blink enough when we are using devices such as cell phones or tablets, and this causes our eyes to dry out. When your eyes are dry, everything is blurry, like looking through a dirty window. Too much screen time can also cause nearsightedness to develop at a more rapid rate in teenagers. It can also cause problems with the focusing system in your eyes. If your focusing system doesn’t work properly it’s harder to switch your vision from near to far making it more difficult to make accurate throws.
It is possible to reach an elite level in sports with vision worse than 20/20, but it will be much harder. The earlier vision problems are detected, the easier they are to fix, so be sure to make an eye exam part of your pre-season routine.
What vision abilities beyond acuity have an impact on an athlete's performance in sport?
There are many visual skills that can have an impact on an athlete’s performance. Some of these include near-far focusing, convergence and divergence of the eye muscles and peripheral awareness. Of these, I would consider peripheral awareness the most important.
Peripheral awareness is mostly subconscious, it controls your spatial orientation, balance, and it helps you anticipate change and movement in your environment. Information from your peripheral vision is typically processed 25% faster than your central vision.
When athletes are “in the zone”, they are often accessing their peripheral awareness which allows them to see and react quicker than usual. The ball will appear bigger and move slower to athletes that are in the zone.
On the other hand, an athlete that is stressed out will have tunnel vision and poor peripheral awareness. The ball will appear smaller and faster and will be much harder to hit.
Lastly, having good peripheral awareness can prevent injuries. Being more aware of your surroundings helps you avoid other players and dangers on the field. It can also improve your balance and instinctive reflexes which in turn help you prevent injuries.
How can this type of vision be trained, and how much can it be improved?
There are many activities that Sports Vision doctors can prescribe to help train peripheral awareness. This is often the first thing I work on with most athletes because it has so many benefits. Teaching an athlete how to turn this system off and on can help them “get in the zone” more often and can help them greatly improve their performance.
The goal of Sports Vision training is to have a balanced visual system, so any part of the system that is out of balance can be brought back to normal levels through a customized vision training program.
Many athletes already have superior visual skills but these can be enhanced by introducing “loading” activities to make them more difficult. I like to use Senaptec strobe goggles which flicker and temporarily occlude part of the athletes vision to make activities more difficult. Adding balance work to any drill can also make it much more difficult and helps integrate the vestibular system with the visual system.
What are some examples of common sport "mistakes" that really have vision at their root?
There are so many common sport “mistakes” that can be attributed to vision, it’s hard to pick just a few. No matter what sport it is, if an athlete consistently misses, shoots, or throws in the same place it is likely a vision problem. For example, a golfer that constantly misses putts short may do this because his eye muscles cross too far inward causing everything to appear closer to him than they really are. The same example can be used for a basketball player that tends to miss shots short consistently. A receiver that constantly seems to drop balls that are right in his hands may be near-sighted which can slow down his reaction time.
One thing I would like to mention that can tie all of this together is concussions and head injuries. Some studies show that over 80% of head injuries result in some sort of visual problem. Often times the player is cleared to play medically, but may still be suffering from visual problems that are affecting his performance. These problems can include double vision, light sensitivity, and trouble tracking moving objects, just to name a few. It is important for athletes to have baseline vision testing done so that their eye doctor can work with other doctors and training staff on making the decision when the athlete should return to play after a concussion. Optometrist can also help athletes regain some of the visual skills that they lost as a result of a concussion.
So in summary, what I do is three fold. I enhance and improve visual skills to improve athletic performance. I aid in prevention of injuries by enhancing visual skills, and I serve as part of a rehab team by helping athletes regain visual skills after a concussion or injury.
Dr. Brandon Walley