VT and Working Distance

In 2008, Dr. Nathan Flax wrote a compelling and thoughtful piece on Darrell Boyd Harmon which was published in OEPF‘s Journal of Behavioral Optometry (Volume 19, Issue 2). Dr. Flax’s writing, which bears Harmon’s name followed by the title, How I Understand His Work, details the amazing contributions Harmon made to optometry, without himself, becoming an optometrist.  Throughout the article, the reverence held for Darrell Boyd Harmon is clear.  His associations with Dr.s G.N. Getman and A.M. Skeffington only serve to solidify Harmon’s impact upod Developmental Optometry as we know it today.  On Harmon, Dr. Flax writes:

19-2 2008

Fundamentally, his interest in optometry was as a vehicle to improve the educability of children. In classroom design, he was particularly concerned about lighting and its impact on posture for two reasons. One reason was the effect of classroom imposed postural distortions on general health. His early work in the Texas school system was an attempt to document this.  The second reason was to minimize postural distortions, to make the matching of space via the visual system with haptic-kinesthetic space, more easily accomplished. It is this latter objective that led him to introduce gross motor activities that have been taken up by optometric clinicians, and utilized to this day.


Many of us in the Vision Therapy room may be familiar with Harmon, or more specifically, the term “Harmon Distance”. One’s Harmon distance, which is measured from the elbow to the base knuckle of the middle finger when placed on the chin (as shown in the diagram), is the distance Darrell Boyd Harmon believed optimized the opportunity for academic excellence. In Vision Therapy, we use this measurement quite often both in our treatment rooms, demonstrating and assigning home activities, as well as helping parents and patients arrange an ergonomically friendly work environment – such as a sturdy chair, a well lit area, and a solid working surface.

Aside from the perceptual and spatial aspects, working distance can affect the mechanics of vision as well.  A patient who tends to reduce their working distance places additional strain on their vergence system accommmodative system, their eye movement abilities and their central/peripheral integration.  With patients in the therapy room, some of our best work may be in educating on the value of consistent and healthy working distance.

This past February, the publication Mail Online published this article detailing the lengths to which a school in China has gone to help remedy these issues, among others.



For as many other important aspects as there are in the VT room, proper working distance remains in the upper echelon of challenges that can be remedied without a fancy gadget or electronic device.  Educating your patients its value and importance can be a key ingredient in a successful program and a lifelong healthy visual system.

For more information, please take a few moments to read Dr. Flax’s article in the Journal of Behavioral Optometry, as published by OEPF.


Posted on August 19, 2014, in From My Perspective... and tagged , , , , . Bookmark the permalink. 3 Comments.

  1. great blog – it is important to understand where we came from!


  2. michaellievens

    Ha, I’d seen these Chinese pics a few months ago. Pretty neat! The fact that they made the news worldwide is interesting…


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