The Connection between Vision & Balance

Balance, vision & Hearing Working Together

For most of us, “vision” simply refers to how clearly we see things. However, vision has a much deeper impact on our lives than just the clarity of images. It is closely linked to our balance system, which helps us maintain stability and navigate our surroundings. To do this, we need to integrate information from three essential systems: visual (sight), proprioceptive (sensing the position of our muscles and joints), and vestibular (sensing motion and balance through our inner ears). A problem in any of these three systems can significantly affect a person’s ability to interact with the world.

The connection between our balance system (the vestibular system in our inner ear) and vision starts at birth (Tecklin). The vestibular system is the only one that is fully developed and functioning at that time. It plays a crucial role in guiding our balance, which in turn helps shape our vision as we grow. In early childhood, our movement helps us develop our vision. Once we acquire the necessary visual skills, our vision starts to play a larger role in guiding our balance.

Vision & the Brain

Research suggests that between half and two-thirds of the brain is dedicated to visual processing. When our eyes are open, about two-thirds of the brain’s electrical activity is focused on vision. This powerful sense often dominates over our other senses, which can be both helpful and harmful. If the visual system malfunctions and provides misleading information to our other sensory systems, it can significantly impact our quality of life.

Fortunately, the human brain has the remarkable ability to create new pathways and connections throughout our lives, a phenomenon known as neuroplasticity. This ability enables us to develop better control over our sensory systems, enhancing our interactions with the physical world and ultimately improving our overall quality of life.

Vestibulo-Ocular Reflex

Dizziness and a sense of imbalance often result from problems with the vestibulo-ocular reflex (VOR), which helps coordinate eye and head movements, as well as from issues with how well our eyes work together. After a brain injury, it’s common to experience disruptions in balance and movement. This is mainly due to a breakdown in how the vestibular (balance) and visual (sight) systems work together.

This sensory mismatch is similar to watching a TV show where the sound and picture are out of sync. While each element may be fine on its own, when they are combined incorrectly, it creates a frustrating experience.

The good news is that through neuroplasticity, we can retrain these systems to work together again. To do this effectively, it’s important to first identify the underlying cause of the mismatch. With a thorough evaluation and specialized vision therapy, we can address and improve any visual deficiencies.

Vision Specialists

One must take particular care in choosing an Optometrist that specializes in therapeutic vision treatment. Some common titles that we use to describe our specialties can include Developmental Optometrist, Vision Therapist or Neuro-Rehabilitative Specialist. I would recommend finding out if the Optometric Physician is a member of the College of Optometrists in Vision Development (COVD), or the Neuro-Optometric Rehabilitation Association (NORA). These are two of the leading communities with respect to the field of visual therapy.

Functional Vision Exam

A functional vision exam conducted by a Neuro-Rehabilitative or Developmental Optometrist differs significantly from a routine eye exam. In addition to checking eye health and clarity of vision, a functional vision exam evaluates a patient’s oculomotor skills. This includes assessing their ability to track a moving target and quickly shift focus between different targets.

The exam also measures how well the patient can focus on objects and coordinate the use of both eyes to enhance depth perception. We pay attention to how the eyes align at various distances and under different conditions, including when the brain is under cognitive stress. Flexibility is another important aspect; patients should be able to smoothly transition their gaze from one target to another, whether near or far.

Once we gain a comprehensive understanding of how a patient’s visual system functions, we incorporate movement and cognitive challenges into our diagnostic testing.

Understanding how the visual system operates when the vestibular system is activated can help healthcare providers identify issues in sensory integration. It’s also essential to determine whether cognitive processing and the visual system can work effectively together. Since vision plays a crucial role in most of our activities, including movement, it is vital to consider these motor functions during a thorough examination.

Additionally, it is important to ensure a balance between the central and peripheral aspects of the visual system. The central system focuses on providing clarity to identify details of an object, while the peripheral system helps with spatial awareness and motion processing. Acquired brain injuries can disrupt this balance between the two systems, but visual therapy can help restore alignment and functionality.

A thorough examination includes extensive trial framing to understand how different prisms and filters affect a patient’s performance. Prisms are special lenses that can bend light and change a patient’s perception of space (Suter). For patients who have experienced a traumatic brain injury, their perception of space may be disorganized or even absent. This can lead to frequent collisions with objects or a general sense of unease while moving around.

When used correctly, prisms can help these patients regain awareness of their surroundings and improve their spatial organization during therapy. Similarly, filters allow us to explore how adjusting different wavelengths of light can impact a patient’s experience. Some patients may find certain wavelengths calming, while others might use colored filters for specific tasks, such as reading on a computer.

Treatment

When a patient has adequate anatomical structures in their vision and balance systems, various deficient skills can often be improved through consistent effort and guidance from a skilled therapist. If the patient is diagnosed with a vestibular-visual dysfunction, a multidisciplinary treatment approach involving both vision and vestibular therapists is usually most effective.

Vision therapists focus on maximizing the patient’s visual skills while gradually introducing tasks that involve different sensory inputs. Neuro-Rehabilitative Optometrists begin by isolating specific visual skills and working to enhance them according to the patient’s capabilities. The therapy is based on the principle of neuroplasticity, which means the brain can adapt and form new connections.

Treatment starts with a specific visual skill in mind, and the patient is presented with a task that requires them to use that skill. As the patient engages with the task, they improve their specific skills and also develop a greater awareness of their body. Learning occurs neurologically when patients are faced with new and challenging tasks that encourage them to adapt and grow. As the patient’s mastery of a specific visual skill increases, we continue to load the task so the patient is constantly being pushed to new levels of achievement.

Visual therapists use a variety of exercises tailored to each patient’s needs. The key is knowing when to introduce these exercises and how to adjust their difficulty. A major part of a patient’s success is understanding how to better control their visual system, so it’s essential to guide them carefully to develop the right neurological patterns.

For example, a therapist might have a patient perform specific movements while wearing different types of prisms. This technique can help the patient reorganize their sense of spatial awareness. Depending on the patient’s diagnosis, prisms can be used to highlight different aspects of their spatial and body awareness, or to gradually increase the complexity of tasks as the patient improves.

Similarly, different lens strengths can enhance sensory awareness and provide an appropriate level of challenge. Therapeutic lenses, including prisms and other specialized lenses, are often used by Rehabilitative Optometrists to influence the brain’s neural pathways, effectively rewiring the brain in ways that go beyond simply improving clarity of vision.

This can be reliably measured using tools like Visual Evoked Potentials (VEPs), Electroencephalography (EEG), and functional Magnetic Resonance Imaging (fMRI). These instruments help scientists scan the brain.

Once patients have developed enough visual skills, we can begin to incorporate head and body movements into their exercises. This integration allows patients to receive feedback on their visual performance while gradually reactivating their vestibular system, linking the two systems together again. This process resembles childhood neurological development, where one system helps to enhance the performance of another.

As we improve our understanding of brain functioning, we increase our ability to facilitate positive changes in patients. For those experiencing balance issues, recognizing the important role of vision may be crucial in guiding them toward the help they need.

Author: Dr. Nathan Davis, OD