When a young child struggles with writing, the immediate instinct is to look at hand strength or pencil grip. However, the true culprit often lives deeper in the nervous system: unintegrated primitive reflexes. These are automatic movement patterns that help babies survive and develop. If they fail to integrate naturally, they force the body to fight itself, destroying posture and disrupting basic eye movements.

 

The Vision-Body Connection

To write or read comfortably, the eyes must move smoothly across a page without requiring the entire head or body to turn. Three key primitive reflexes directly impact this balance:

 

  • Symmetrical Tonic Neck Reflex (STNR): This reflex causes the arms to bend when the neck flexes forward and straighten when the neck extends back, which sets the stage for crawling. If not integrated, this can make it exhausting to sit upright at a desk.

  • Asymmetrical Tonic Neck Reflex (ATNR): This reflex is known as the fencer’s pose. Turning the head causes the arm on that side to extend, locking the hand and preventing independent eye movements across the midline.

  • Tonic Labyrinthine Reflex (TLR): This reflex is triggered by head movement, it features a forward flexion pattern (curling inward of limbs) and a backward extension pattern (straightening outward).  Having this reflex not integrated can cause frequent loss of balance when tipping the head. 

 

Together, these reflexes prevent a child from keeping a stable posture while isolating eye movements from body movements. There are many other primitive reflexes that also contribute to the stability of vision. 

 

Retinoscopy and Functional Approach

When body posture is unstable, standard eye chart prescriptions often fail. Dr. Ho uses free-space retinoscopy (instead of relying on the auto-refractor measurements alone) to evaluate how patients engage their vision in real-world space. This allows her to prescribe functional lenses optimized specifically for visual function and spatial alignment, rather than simple clarity. The autorefractor is a device that sends a beam of light and calculates prescriptions based on mathematical calculations from the light being reflected by the eye. While it is useful information, it often errors with high prescriptions, patients with eye turns or difficulties focusing on the target, or young patients with active focusing systems.

For clinicians interested in learning more about retinoscopy, Dr. Ho recommends Bubba’s Just Look Retinoscopy technique.

 

Last week, a young patient with Down’s syndrome presented with severe writing difficulties and more than four unintegrated reflexes. After evaluating her spatial engagement, Dr. Ho prescribed functional lenses. The child immediately improved her heel-to-toe walking. With her old glasses she repeated swayed both arms past her midline to keep balance when doing this task. Her mom burst into tears, seeing firsthand the massive impact vision was having on her child’s development beyond writing alone.

If your child struggles with posture, clumsiness, or handwriting, the eyes and body may be out of sync. Sometimes these reflexes also re-emerge in adults after a major brain injury as well.  

 

Updates and Events

Dr. Jamie Ho will be presenting a continuing education course: Hemifield: Evaluation and Management at the Duck River Optometric Society during the last week of September 2026. She presented this course first at Middle Tennessee Optometric Society earlier this month.