Harmon Distance: What is it and why should educators know what it is?

Perhaps you have heard of a slant board, or encountered one while stepping inside the OT or special education rooms in your building. Unfortunately, “special” items like a slant board are often reserved for special education classrooms. I am making it my mission to educate general education teachers about simple items that they should have access to for their students.

Let me start by stating that I am not sure who allocated school funding towards plastic counters and non-kinesthetic letter tiles with magnets that fall out on day two, but I would seriously like to speak to them. Why are we more concerned with buying cheap items in mass then making available research-backed items that assist students with needs that are not actually “special” they are just needs. Needs like proper lighting or comfortable seating. How about being able to sit comfortably while reading a book?

Harmon spent three years of compiling an inventory of physical and psychological difficulties of Texas school children.  The children were given thorough pediatric, dental and psychological examinations.  Visual, educational, medical and dietary tests were also conducted.

Dr. Harmon discovered, among many shocking results:

  • 53.3% of the children had visual difficulties
  • 30.2% of the children had postural difficulties
  • 20.9% had chronic fatigue

Harmon concluded that “posture relates not only to spatial judgments, but also to performing visual tasks.”  As Dr. Martin Birnbaum notes in his book Optometric Management of Nearpoint Vision Disorders, “to perform any task, a person must come to balance with gravity and then the particular task at hand…(If they don’t), a person must expend energy to perform the task easily and efficiently.”

In other words, if your body is out of balance with the environment, it will take energy to compensate.  Harmon wondered what would happen if the children’s environment were improved.  How much impact would this have on their vision and overall performance?

“Heredity supplies the materials of which environment makes the man”

This quote by Dr. Harmon, not exactly PC with its gender-reference, makes a clear point.  He writes, “Eyes are not cameras…meaningful vision is learned – learning like every other learning – by doing, by the constructive use of bodily stress.”

How we interact with the environment can lead to significant impacts on our visual system.  For example:

  • When eyes are too close to the printed page, whether from poor posture and/or improper desk height, the greater the eyes must converge.
  • If a child is in an unbalanced posture (see picture 1), there can be a significant difference in the torque, force and compression of the intervertebral disks of the spine.
  • When a child has to view a book on a flat surface, it can exceed his or her visual tolerances.

To solve the problem, Harmon analyzed data from many fields and planned a “coordinated classroom.”   He remodeled classrooms to improve “daylight control, artificial lighting, seating and seating arrangement and room decoration.”

Harmon raised the work-surface to a 20 degree angle, bringing the surface more parallel to the face.  This significantly reduced the compression of the intervertebral discs.    He also controlled the lighting, and turned blackboards green.  (You remember blackboards, don’t you?)


Viewing surface:  Ideally, your face should be parallel to either your book or your computer screen.  (See picture 2.)  Follow the Harmon Distance, and use the slant board when reading.

Harmon distance, slant board

Picture courtesy of Visual Edge

Posture:  What is your body doing?  Is the placement of this paper centered or is it off center from the plane of regard?  Your feet should be flat on the ground, and your legs should form a 90 degree angle.  Try not to slouch – remember you’re wasting energy.

Harmon information from (Mischio)

So, still not convinced that these items are essential and not “special”?

Read the entire article here:



Here is how I created a fully adjustable slant board for $7

  • Velcro
  • Packaging tube
  • Wooden canvas from Michaels
  • Clipboard

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