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Harmon's Distance and Classroom Ergonomics
 

After last month's newsletter, we received a few questions regarding "Harmon's Distance" - what it is and how it applies to a child's learning. Here, we will go into more detail on this concept of an optimal working distance and also how we can encourage proper classroom ergonomics for our children.
Harmon's Distance is considered the optimal visual distance for reading and other near tasks. It is measured by placing a closed fist under the chin and then holding the near-point target, such as a book, at the tip of the elbow. The target should not come any closer to the eyes than this set distance.
This concept was based on the research of Dr. Darrell Boyd Harmon who, although not an optometrist himself, made a huge impact on behavioural optometry as he worked with leaders in the field, such as A.M. Skeffington and G.N. Getman, more than sixty years ago. 
Harmon devoted much of his career to studying the growth processes in children, particularly those related to vision and their learning environment. Harmon's research showed an improved learning performance when the proper conditions for near work were established. One of his greatest works, "The Coordinated Classroom", was the culmination of nine years of research and the analysis of 160,000 children. In his book, Harmon outlined how to remodel classrooms in order to reduce concerns initiated by poor postural habits. Harmon argued that poor posture in the classroom can warp a child's growing body, causing visual problems. He states, "The human body is an organic mechanism fitted to survive by its capacity to adjust itself or its relationship to the environment in which it finds itself - to go into action to establish balances with the forces and restraints which surround it such as gravity, light, sound, temperature...To survive and grow in such a surround, the organism then must and does make compromised adjustments...compromises which can use energy excessively, warp structure, or delimit or deviate the purposefully directed performances of the growing child." That is to say, if a child's body is out of balance with his/her environment, he/she must exert extra energy in order to compensate. 
How a child interacts with the classroom environment can lead to negative impacts on his/her visual system and thus, academic performance. If the near-point task is held too close (ie, inside of Harmon's distance) due to poor posture or improper desk height, there is a greater demand on convergence and accommodation, which can lead to eyestrain, headaches and inefficiency while reading. If a child is in an unbalanced/slouched posture while at his/her desk, torque, force and compression of the inter-vertebral disks of the spine can occur. Slouched postures also bring the eyes closer to the printed page creating a reduced working distance and causing the eyes to over-converge and over-accommodate. Eye movement ability and central/peripheral integration is also compromised when working distance is too close. The induced eye fatigue can result in a child losing his/her place while reading, skipping words, misreading words or avoiding near tasks altogether.
Harmon placed a strong emphasis on avoiding flat desks in the classroom. When viewing a book on a flat surface, the body has to lean forward in an attempt to bring the page more parallel to the face. This added stress on the back muscles encourages the child to support his/her head with one hand, thus creating an asymmetric posture. In contrast, a slanted work surface of 20 degrees encourages the child to sit upright and position himself naturally to work within his Harmon's distance. 
You can ensure your child is maintaining proper posture while reading and doing homework by following some of these simple suggestions:
- Have your child use a slant board like the one pictured below for all reading and near work activities. Ideally, the work surface should be slanted upwards by approximately 20 degrees.
- Teach your child how to check his/her own Harmon's distance (measured by placing a closed fist under the chin and placing the book at the tip of the elbow).
- Ensure lighting is evenly distributed across the whole work surface with no shadows or areas of glare. Natural lighting is best.
- Ensure your child's desk height is appropriate - look for a 90 degree bend at the ankles (feet flat on the floor), the knees, and the hips, as pictured in the illustration below. 
As adults, we have become increasingly aware of the importance of proper ergonomics in our workplace environments. From proper lighting, to the correct type of chair, to optimal desk height; we know the importance of how these elements come together to create an optimal work environment. We need to extend these principles to our children, both at home and in the classroom, to ensure they are set up to achieve visual and academic success. 


 
"All of us are well aware that, no matter how accurate their optical function must be, eyes are not cameras... Meaningful vision is learned - learned like every other learning - by doing, by constructive use of bodily stress... This integrating, checking, comparing, redirecting, and abstracting , taken together, make for the structuring of meaningful vision."

- Dr. Darrell Boyd Harmon
We are thrilled to be hosting Dr. Carissa Doherty and Dr. Danielle O'Connor, naturopaths from Natural Care Clinic, as they present a series of complimentary seminars at HVTC over the coming months. We encourage all parents of our vision therapy patients to come join us for these lectures, as the overall health of your child is closely linked to the health of his/her visual function.
We look forward to learning with you! 

Tuesday, February 21,  2017 (6:30 – 8:00 pm) -
 Digestive Health

Tuesday, March 7, 2017 (6:30 – 8:00 pm) - 
Detoxification - How to Survive in the 21st Century

Tuesday, March 21, 2017 (6:30 – 8:00 pm) - 
Balanced Hormones

Happy Valentine's Day from all of the vision therapists, staff and doctors at HVTC. We hope you feel loved and appreciated on this special day...because you are. ❤ 
Copyright © 2017 Halton Vision Therapy Center, All rights reserved.


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