Tracking

Tracking is the ability to control where we aim our eyes.  Technically, the control of our eye movements is called oculomotor skills.  This skill is critical for everything from sports to reading.  Good tracking skills allow us to hit a baseball or follow a line of print without losing our place. In school, if a child cannot track from word to word smoothly, accurately, and efficiently, reading suffers and comprehension drops as words jump around and meaning becomes muddled.  Tell-tale signs of tracking problems in school include frequent loss of place, skipping  or transposing words, omitting entire lines, using a finger to follow print, moving the head rather than just the eyes, and poor comprehension because of scrambled text.

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TRACKING PROBLEMS DURING READING

Normal:  Accurate eye movements along a line of print.  Smooth return sweeps to the beginning of the next line.

Tracking Deficit:  Eyes jump backward and forward and fall on lines above or below during return sweeps.

There are three basic types of eye movements:

• Fixations: ability to hold eyes steady without moving off target
• Saccades: the ability of our eyes to make accurate jumps as we change targets
• Pursuits:  the ability of our eyes to follow a moving target

Fixation

Fixation is the most basic eye movement skill from which other skills grow.  Good fixational skills allow us to maintain a steady gaze without our eyes moving involuntarily off target.  This allows images entering the eye to be centered on the fovea, the part of the retina that gives us our clearest vision.  Without the ability to fixate, images will be blurry and confusing.  In school, comprehension suffers as our eyes involuntarily move off the print and words jumble or jump around. Inadequate fixation skills must be addressed early in a treatment program before other oculomotor techniques are attempted because it is the foundation skill upon which others build.

CLICK HERE TO GO TO THE FIXATION EXERCISE PAGE

Saccades

Saccades are eye jumps–the sudden, quick voluntary change in fixation from one object to another.   Saccades involve any shift in gaze, such as from road sign to speedometer, board to paper, notes to computer screen.  During reading, accurate saccadic movements are critical.  The eyes must move left to right along a straight line without deviating up or down to the lines above or below.  In addition, when we reach the end of a line, our eyes must make a difficult reverse sweep back to the beginning of the next line.  If a child cannot control these eye movements, he’ll lose his place and comprehension becomes a problem.  The ability to make accurate saccades involves a very precise coordination between our central and peripheral visual systems.  Our central vision processes what we’re looking at in clear detail and defines what we’re seeing (“What is it?”) while our peripheral vision simultaneously locates the next target to let us know where to aim our eyes during the next saccade (“Where is it?”). If there is not a continuous, fluid, simultaneous integration between the two systems, saccadic eye movements will be poor.

CLICK HERE TO GO TO THE CENTRAL-PERIPHERAL EXERCISE PAGE

Pursuits

Pursuit eye movements are used to follow a moving target.  Accurate, smooth pursuit eye movements allow us to make spatial judgments as to the speed and position of the moving target.  Pursuit eye movements are especially important in driving and sports.  To evaluate pursuit movements, parents can randomly move a small target about 20 inches in front of the child’s eyes and observe the following:  Does the head move with the eyes?  How accurate are left-right, up-down, z-axis movements, and rotations?  Does the patient falter at certain positions of gaze? How quickly do he/she correct?  Is the patient tense, rigid, wiggly, or needing encouragement to complete the task, indicating the effort they must exert?  Does accuracy degenerate with time?

CLICK HERE TO GO TO THE PURSUIT EXERCSIE PAGE

SEQUENCING EXERCISES:  Generally, oculomotor exercises should progress from monocular (one-eyed) to binocular (both eyes), steady fixation on a stationary target to saccades and pursuits, large targets to small, large eye movements to small for saccades and small to large for pursuits, slow to fast—all the while working to eliminate head movement and establishing accuracy, ease, and automaticity with oculomotor skills.

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Parents: If your child has difficulty with these activities, it could indicate he/she has an undetected vision problem.  Talk to your family eye doctor or contact a developmental optometrist for further evaluation.  To locate a doctor in your area, go to covd.org.