The 24 Distinct Skills of Vision
By Jonathan Bailin, Ph.D. & Dr. Gary Polan, O.D. Sports Medicine & Ergonomics Associates
Submitted in 1997, Updated 2016
Most aspects of training for elite athletes have been detailed with one exception, the “Final Frontier” of vision. Visual skills are essential to performance in sports and reading, but can they be improved? Yes! This article will describe the many individual aspects, or eye skills, needed to perform sports and read at peak efficiency. FACT: All visual skills are learned! Yours can be improved through the modern science of Vision Training (VT) or Sports Vision Training (SVT). This article will provide the details.
The author has collaborated with his associate, Dr. Gary Polan, O.D. many times. Dr. Polan has been a pioneer in the field of Sports Vision Training (SVT) and Vision Training (VT) since 1984 (*). In 1996, Dr. Polan's work received corroboration by the staff at the Jules Stein Eye Institute at the UCLA Medical School (**). In this article we outline all the individual skills required by the visual system to perform at its peak that now form the science of VT and SVT.
Dr. Polan’s experience in training and improvement of visual skills has resulted in inspiring advances in most learning disabled cases. Improvements in intellectual activity which, are generally unexpected but very welcomed by parents, have not been well documented by rigorous research designs to date. Still, we are confident that interactive fitness products (eg xergames.com) also will play a significant role in improving reading skills, Attention Deficit Disorder (ADD), and Dyslexia.
Few realize that reading is a motor activity like sports. Dr. Polan's experience in training and improvement of visual skills has resulted in "surprising" advances in most learning disabled cases. Improvements in intellectual activity, which are generally unexpected, but very welcomed by parents, have not been well documented by rigorous research designs to date. Still, we have seen that VT/SVT can play a significant role in improving reading skills, Attention Deficit Disorder (ADD), and Dyslexia.
Just one of many common reading flaws is transposing letters like "ea" to "ae". When the number or severity of flaws affects performance or comprehension, VT or SVT is warranted. But before any improvement in reading or athletic performance can take place, the visual system must be engaged. What are the exact skills that the eyes posses that can influence their performance?
Visual Skills Sub Areas
First, readers of this treatise should realize that ALL visual skills are learned. Take note that the last statement of fact is the key to the whole field of vision therapy. From infancy, the vision skills that we take for granted have been built gradually over time. Contrary to folklore, they are not precisely genetically predetermined and can be improved. This leads us to the next principle of SVT.
Visual skills, no matter how polished by our activities or sports, can be improved in a clinical or private practice setting. Sports careers, worth millions of dollars, can be improved and lengthened past their usual expirations. One of Dr. Polan’s more famous patients Carl Lewis says that, more of his records would still be standing today had he practiced SVT during his competitive career.
Visual skills can be divided into 3 sub areas: Visual Acuity, Visual Efficiency, and Visual Processing. Visual Acuity is measured by standard optometry tests commonly used for eye prescriptions including standard eye chart examinations.
Visual Efficiency can be measured by testing among the 24 areas listed below which include focusing, convergence, divergence, etc.
These areas are examined toward improvement of reading and sports.
Visual Processing is a subset of Visual Efficiency. It can be evaluated by tests, which measure the extent of learning disabilities such as Reading Disorders, Attention Deficit Disorder (ADD), and Dyslexia. Items 2, 7, 15, 16, 18, 20, 21, 22, and 24 below are closely evaluated. Most ADD and Dyslexia is responsive to treatments for visual/perceptual deficiencies in these areas of training. These disabilities are often diminished or alleviated completely.
Visual Efficiency & Visual Perceptual Skills
All movement mechanics during sports are enhanced by eye skills and eye health. In turn, improvements in several areas of eye skills will enhance eye performance during motor activity. For example, reaction time is first dependent on the visual accuracy and recognition skills listed. To acquaint the reader with vision training potential, a brief review of each eye skill, which can positively affect motor performance, must be considered.
1) Visual Acuity-is your ability to achieve a sharp resolution of an image. It can be divided into Static Acuity (stationary images) and Dynamic Acuity (resolution of images in motion).
a) Static Visual Acuity–corrected or not, your eyes should have 20/15 vision for high-speed activities. “20/15” vision means that you see at 20 feet what the average person only sees accurately at 15 feet away.
b) Dynamic Visual Acuity–is the ability to see sharply while the player, opponent, and ball are all in motion. This ability is made up of many other skills such as Convergence, Focusing, Tracking, and Interpretation, etc. Following the action with the eyes rather than the head or body is more efficient and puts less stress on the balance and muscular-nervous system.
2) Visualization—is the ability to plan, imagine, and prepare for upcoming motor skills and movements. Some sports scientists believe visualization of needed skills is more efficient than coaching “pep talks”.
3) Peripheral Vision–is critical to awareness of other important things while watching the ball such as your teammates, boundaries, or opponents.
4) Depth Perception—is the ability to quickly and accurately judge the distance between yourself and your opponent, teammates, targets, and boundary lines while judging the speed, rotation, and flight path of the ball. Billy Jean King rates this above court speed and eye-hand coordination for junior tennis players. Those who stare during the day, such as students, programmers, and executives, quickly diminish this skill. Importantly, that person may play poorer tennis during the week than on the weekend for this reason.
5) Visual Pursuit—is the ability to use the eyes to follow a moving object smoothly and accurately at speeds that allow head movement to participate. This critical skill is based on good eye teaming and eye muscle balance but it cannot track a ball smoothly at high speeds. At about 50 MPH, Saccadic Movement takes over.
6) Saccadic Movement--is the ability of the eyes to “jump” from one point to another when object speeds exceed those of Visual Pursuit. This skill is used in reading to jump from one word to the next. If this skill is poor, reading ability is affected! Quick, accurate saccades are used to survey rapidly with as little head movement as necessary. Head movement is a less efficient method of eye tracking and can confuse balance. Unnecessary head movements, and eyelid reflexes to flinch, must be overcome with training.
7) Visual Concentration--describes the cooperation between Visual Pursuit, Saccadic Movement, and Visualization in the “minds eye” or imagination. This skill is not scientifically well defined yet, but is exemplified by tennis players who must switch concentration rapidly from target, to ball, to processes of planning and prediction which are critical to performance.
8) Speed/Flexibility of Focusing--is the ability to shift focus from near, intermediate, and far distance. This eye muscle skill is subject to the same fatigue, which affects other muscles over the course of exercise.
b) Accuracy/Efficacy of Focusing—is the ability to do the above precisely and without wasted effort.
9) Glare Recovery Speed-is the ability to see clearly after looking toward intense light. Focusing near sun, and at tennis court lights, causes “dazzle” to the retina, or a “whiting out” of images.
10) Scotopic Sight-is the ability to see with dim illumination.
11) Eye Muscle Stamina--is the ability to withstand fatigue without decreased performance in a variety of eye tasks.
12) Color Perception—is not critical but may play a role in optic yellow against white lines and line calls in tennis. Note that “Color Blindness” is a misnomer as there are many gradations of color deficiency. Color deficiencies may interfere with Contrast Sensitivity (see #19). Does a basketball player with color deficiency see a red hoop as easily as other players or does it blend into the background more?
13) Eye Dominance—is the ability of the sight in one eye to dominate images from the other. Tennis players generally prefer strokes on the same side as the dominant eye, which is usually the right eye for right-handed players, over 80% of the time.
14) Fixation Ability-is the skill of preventing eye fatigue, which comes from staring at objects too long. Tennis receivers, with poor fixation skills, fatigue within a few seconds of staring at the server. Other players do not, but staring should be avoided. Staring at computer screens can negatively impact athletic ability.
15) Visual Memory—is the accumulation of past experiences such as the number of proper swings logged in players “motor program file”. This combined with visualization for future swings is probably a major factor in consistency during competition. Visual Memory fades with time.
16) Spatial Localization—is knowing your position relative to other objects especially while you, ball, and opponent are moving.
a) Esophoria—occurs in players who see the world CLOSER than reality. They tend to mistakenly hit/throw more short. We believe Shaquille O’Neal was a good example of this, especially during end of game free throws.
b) Exophoria–occurs in players who see the world FARTHER than reality. They tend to hit/throw mistakenly longer.
17) Speed of Recognition Time--is how fast you can identify images.
b) Reaction Time–is how fast can you react to those images.
18) Eyes to Body Coordination–is the ability to integrate what you see into an appropriate and coordinated response from your body parts (aka: Visual/Motor Integration). Note that the expression “Hand Eye Coordination” is a misnomer and should be expressed as “Eye Hand Coordination”.
19) Contrast Sensitivity—the ability to pick out an important object against a field of other objects, all in the distance. Examples are a white baseball against a cloudy sky. The grey on grey is a low contrast image. A white baseball against a black sky is a high contrast image. A yellow tennis ball against a blue court is another high contrast image.
20) Visual Attention--is the skill used to prepare the eyes and brain, which heightens its readiness for an upcoming task. This is a precursor to Visual/Motor Organization. Of course, the body can influence this system which is one reason why elite tennis players bounce during the opponents contact.
21) Figure/Ground–is the ability to pick out an object in the foreground against a variety of background fields; to discriminate the figure to be attended to and see the interrelationships to its background information. Lower game scores appear to indicate that basketball shooters suffer in unfamiliar surroundings such as larger arenas and unfamiliar lighting conditions at Final Four locations.
22) Visual/Motor Organization–is the ordering and organization of motor skills; to choose from a “catalog” of motor programs for meaningful and productive action.
23) Jump Duction–the ability to move from visual tasks that require convergence to divergence of the eyes and back. Jump Duction deals with vergence; the activity of the extraocular muscles to diverge for distance, and converge for near objects rapidly and efficiently.
24) Tachistoscopic Skills—are the ability to recall an image that appears too fast to be consciously recognized but may be recalled by a visual image (see #17).
These skills help sound and sight skills complement each other during visual processing. It is the auditory/visual integration ability, which coordinates inputs into a meaningful perception and shifts priority and attention from one to the other when necessary. Years ago, preventing air traffic over the US Open tennis tournament in New York was initiated for this reason. Receivers had to hear the serve as well as see it.
Note--Auditory specialists can better assess the ability to discern background from foreground sounds similar to the way vision training will assess background to foreground objects. This is an area worthy of much more study because there is great potential to design audio triggers, cues, and scoring tones here. Consider the starting buzzer for an Olympic swimming race and bell for a horse race!
The list of “Visual Skills” above items 1-24 is Copyright (c) Jonathan Bailin. Ph.D. 1997, 2016. Reproduction by author’s permission only.
* Hoffman, L., Polan, G., Powell, J. The relationship of contrast sensitivity functions to sports vision” Journal of the American Optometric Association 55:10,747-752, Oct 1984. ** Laby, Rosenbaum, Kirschen, Davidson, Rosenbaum, Strasser, Mellman “the visual Function of professional baseball players” American Journal of Ophthalmology 122:4,476-485. Oct. 1996.
Keywords: sports vision training, SVT, vision training, VT, eye skills, reading skills, sports performance, sports career enhancement, visual acuity, visual efficacy, motor learning, eye performance, eye health