What’s the difference between “Instantaneous Testing” and “Performance Based Testing ”?

Any typical vision exam always includes a check for clear vision. School screenings, pediatrician screenings, and visits to an eye doctor (Optometrist or Ophthalmologist) will follow procedures necessary to check for clear eyesight.

However, if eye exam results indicate clear eyesight, it is important for you to understand that this does not mean your child has been cleared of having a vision problem that may interfere with learning. Too often, after years of struggle, we find children with serious vision problems that easily passed all prior vision testing.

According to the educators Allen and Virginia Crane, in their book Buzzards to Bluebirds (Wolf Creek Endeavors) the key is performance based testing.  The Cranes described a regular eyeglass or medical eye exam as “Instantaneous testing.” This type of testing determines if the child has “clear and single vision” right now, right here.

But if the child does have “clear and single vision” during the exam, the unanswered question is: “can they sustain that clear single vision for a sustained period of time?” To understand how a child can pass a vision screening and also have a serious vision problem that interferes with learning, it is critical that you are aware of this difference.

Viewing the letters on an eye exam chart for a few seconds is not the same as viewing text on a book’s page, the screen of an electronic device, or words on a whiteboard at school. Learning-related activities require repeated and coordinated eye movements, prolonged effort, and visual skills that require processing and associate meaning with images.

Many vision problems will remain hidden if a child with learning problems is not properly evaluated. “Performance based testing” is exactly what a functional or developmental vision exam is. It seeks to determine whether the child is ready to learn visually.

An optometrist who specializes in functional or developmental optometry is trained to test the following areas of performance in your child:

  • Processing speed and accuracy: Reading words, sentences and numbers quickly and accurately
  • Selective concentration: Staying on a visual task, even with distractions present
  • Visual memory: Accurately remembering what is seen
  • Letter reversals: Confusing letters such as b, d, p and q.
  • Visual-motor integration and speed:  Eye-hand coordination and speed
  • Visualization: Creating a mental picture in the mind that is used to solve a problem

Before you can determine whether or not your child has a vision problem, you have to rule out performance based vision problems. For more information and to download our free guide “10 things you need to know about vision” please click here.

Dr. Philip Nicholson is an Optometrist who specializes in functional and developmental vision care located in Olney, MD, convenient to Silver Spring, MD.  If you suspect your child might have a vision problem that is interfering with learning, contact us to schedule an appointment for a thorough vision assessment.  The good news is, if your child does have a learning-related vision problem, a vision therapy program can help.

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