Let me take you back about a year ago… It was early on a Monday morning and I was sitting in vision therapy lab learning the basics of the DEM test, eagerly taking down notes along with the rest of my classmates. I had my glasses on top of my head (I am a low myope) copying notes, the girl next to me had her head tilted to the left, another had the paper tilted at a 45 degree angle and the girl on the end had her head about 10 inches from the desk. We were all oblivious to our postures until Dr. Arnie Sherman said, “ Stop! Look at how you all are sitting!”
I have to be honest at the time I did not fully understand why he was so animated in the fact that we all had made these adaptations to make ourselves comfortable. I never really thought twice about why I took my glasses off or sometimes tilted my paper or my head while I was writing. Now that I have been in this VT centered externship, I am beginning to get the importance of a proper working distance and posture.
For those of you who don’t know, the appropriate working distance for near work is something called, the “Harmon Distance.” This distance is from your fist held at your eye to your elbow on a desk (some people consider it your fist at your chin to your elbow on the desk… I feel that these are close enough; so you choose which is more comfortable for you).
In doing research for this article, I stumbled across an article by Sarah Cobb called “Harmon Revisted”, an article that reviews Harmon’s research and specifically a book known as the “ The Co-Ordinated Classroom.” She focuses on all the factors that affect a child’s posture, stressing that these adaptations that we make have lasting effects on our visual system. As per Harmon, Cobb was able to project that “poor postural habits actually warped a child’s growing body causing many of the visual problems that we, as the behavioral vision care team, treat daily.” 1 The article is quite extensive and touches upon things such as how desk height, lighting and the work surface play a role in determining a child’s visual posture as they are performing near work. As important as those things are, today I just want to focus on the Harmon Distance, which I believe is one of the most important contributions Dr. Harmon made.
It seems simple: maintain a proper working distance and you will (theoretically) be ‘visually comfortable.’ If your patient is complaining of fatigue and eye strain, take a look at how they perform their near tasks. It could be that they are sitting closer than they should, requiring them to over-exert their accommodative and vergence systems. What this translates into is muscle fatigue, lack of attention, oculomotor dysfunctions and avoidance. Yes they may truly have an accommodative insufficiency or a CI, but by implementing an appropriate working distance it could eliminate a stressor that is exacerbating their condition and making their system work harder.
Start with yourself: Do you maintain a proper working distance? Are your feet on the ground with your head straight while you are reading this? How about when you are doing Michigan Tracking during vision therapy with a patient- are you aware of how they are sitting? What is their head posture?
Part of being a good doctor (and vision therapist!) is observation; that is, the child may be able to complete the task, but how are they doing it? You want to see how they are functioning and what adaptations they have made so that you can teach them the proper, least stressful and most efficient way to use their eyes.
I promise by just making this simple change in encouraging patients to work at their Harmon Distance you’ll see a difference in their comfort level!
** Please visit this article; it really is fantastic!
1) Cobb, Sarah. “Harmon Revisted.” The Vision Therapy Center, n.d. Web. 27 July 2012.< http://info.thevisiontherapycenter.com/Portals/91892/docs/Sarah%20Cobb%20Harmon%20Revisited.pdf >