Nothing delights a child more than building and decorating a gingerbread house during the December holidays. But that same activity also can provide insight into children’s sensory processing, visual perception, and overall awareness of the world around them.

How so? Watch carefully. Some children do meticulous layouts and undertake detailed planning, ensuring straight lines on the roofs of their gingerbread houses. Others begin building immediately, with scant attention paid to purpose, structure, and design. The planners may follow up their building work with elaborate candy decorations, oftentimes equally spaced and color-coordinated, while other children simply decorate part of the house or place candy in helter-skelter fashion with little consideration – or, perhaps, lack of understanding – for appearance.

Imagination is not an escape from reality. It represents a much deeper immersion into the world around us. As optometrists, we well know that imagination and awareness govern where our eyes move and how information is processed. Children whose worlds are more internalized or who are withdrawn from what is outside them are more likely to see and act differently – even significantly differently — from those with better developed visual processing skills.

As I have described in prior blogs, visual processing has many parts. One of them is retinal processing which refers to the brain’s ability (partially beneath a conscious level of awareness) to filter incoming sensory signals, sending the filtered version for further brain processing. This further brain processing combines the retinal signals with other sensory signals (from hearing, smell, taste, and touch), synthesizes the information, and then reacts and responds, depending on many internal sensory signals.

When intact, retinal processing enables people to have internal systems (such as balance and posture) running automatically. This “cruise control” allows a person to respond appropriately to the external world around them. If brain circuitry is out of sync because it has been disrupted – or, in the case, of younger children, perhaps underdeveloped — people can become confused about their surrounding environment and exhibit inappropriate reactions and responses.

I mentioned how imagination and awareness govern eye movement. Indeed, central eyesight represents only a tiny portion of a person’s view. The place where central attention is directed to see details is governed by peripheral retinal stimulation, which represents approximately 94 percent of a person’s view. Signals from the retina’s periphery are what directly impact key brain structures, including those affecting balance, posture, and motor skills, and important physiological systems, including mood regulation and fear. These peripheral signals are also needed for spatial mapping, so that sensory integration linking what is seen with what is heard, along with the other senses, can occur. Signals from central eyesight, however, occur more slowly, and only after a person is consciously attentive and focused on a specific target.

Proper retinal processing is critical to learning, and learning, of course, serves as the foundation for imagination. The more we know and understand, the more creative as adults – and children – we can be. We are able to think out of the box.

I have been a vocal proponent for the passage of laws that go beyond simple eyesight and hearing screenings to include mandatory eye-ear synchronization testing, particularly in children before they enter school. Sensory integration, which underpins effective retinal processing, is crucial to a child’s ability to learn and develop proper motor skills, including eye-hand coordination. Peripheral retinal signals play a crucial role in that synchronization of the senses.

This year (2021), I was invited to address an assembly of international neuroscientists attending the annual Neuroscience20 (N20) Summit, held virtually in Rome, Italy. The purpose of the gathering was to discuss health care policies as they relate to the health of the central nervous system – brain health, spine health, and mental health — and to present recommendations to political leaders attending the G20 Summit in Europe. I led a discussion team consisting of five other researchers who studied brain function through the eye, using a variety of measures, such as cerebral and ocular blood flow, retinal excitation, and photoreceptor activity, to diagnose degenerative disorders like Alzheimer’s disease and macular degeneration. Genomic analysis also was featured as a way of assessing gene mutations that lead to those (and other) diseases.

The retina is part of the central nervous system and acts as a primary portal for information to the brain. Environmental signals in the form of light pass through the retina and are converted into electrical signals that propagate through neurons and interact with critical brain structures. These include the brainstem, which governs unconscious body control; the visual cortex, where information is processed at the conscious and subconscious levels; and the hypothalamus, which plays a critical role in controlling some aspects of the limbic and endocrine systems.

All inventions can be updated as technology changes. I have been quite active in pressing for modifications in the way standard eye examinations are performed for patients with learning differences, brain injuries, and autonomic dysfunctions. Eyesight testing still emphasizes non-moving targets, even though people depend on their visual processing more to judge moving targets while using computers. 

Knowledge about the eye – and, more specifically, the retina – has grown significantly within neuroscience, including the newer nano-neuroscience. The peripheral retina is often ignored or not emphasized, even though it has a significant impact on how we learn, react, respond, and, in general, process information.

Of course, I digress. Visions of gingerbread houses and the chatter of children building them prompted my narrative. Hopefully, the science presented here will give you greater insight into the sensory integration and retinal processing involved in gingerbread construction. Of course, no science is necessary to enjoy eating them.

This new year – 2022 — marks a special anniversary for me. Exactly three decades ago, I discovered the Z-Bell Test™. Thank you all for following the growth of my 30-year-old “baby!”

Deborah Zelinsky, O.D.
Founder, Executive Research Director
Mind-Eye Institute