Course Notes: PRI Vision Postural Visual Integration


I am still picking up the white matter that exploded all over the pavement as I left the PRI Vision course that was hosted in Grayslake, IL.

It was an excellent experience interacting with Ron and Heidi, and believe it or not they are familiar with my blog…and the corresponding pictures.

Therefore I was the butt of many jokes this past weekend, which definitely made me feel at home with the PRI family that I have so grown fond of.

There is a reason it has taken me so long to put this work up. These notes have been the most challenging I have written yet, as the material was way out of what I have normally been studying.

It is this class however, that solidifies PRI methodology as grounded in neurology. It was two days of brain, autonomics, vision, and optometry. I will do my best to show you what I learned in a semi-understandable manner.

Seeing Visions

Definition – “The deriving of meaning and the directing of action as a product of the processing of information triggered by a selected band of radiant energy.” – Robert Kraskin

Vision is not just what we see, it is what drives us to make decisions.  It is a skill that we develop as we age. It is the dominant sense in the brain, as 70% of the brains connections are related to vision.

Vision can and does become lateralized.

Sight is the clarity of our visual field, which is slightly different from vision. Having more clarity is not necessarily better, as there are many things that we see that we do not take into account and process.

Think about when you get a new car. How often are you now seeing your car brand when you drive compared to before? This realization occurs because your brain has informed your visual system to become more aware of the brand in question.  The desire for a particular behavior drives what information we take in from the environment.

Our environment influences our behavior, and our behavior influences our environment.

Pluses, Minuses, and other Fun Things

 There are several visual concepts that PRI has integrated into its methodology. You need to know this stuff to understand further concepts.

  • Myopia (nearsighted): See better near as space is constricted and leads to system-wide extension.
  • Hyperopia (farsighted): See better far than near. Space expands and leads to system flexibility at low levels.
  • Astigmatism (aka scoliosis of the eyeball): Details are distorted in one direction more than others due to asymmetrical torque on the eyeball.
  • Presbyopia: The lens cannot focus as well due to normal lost flexibility as we age.
  • Accommodation: Ciliary muscle tightens to focus on close objects. Chronic over-accommodation may create artificial myopia because it becomes hard to turn off the ciliary muscle (like contracting a bicep all day then trying to relax).
  • Ambient visual pathway: Seeing the periphery.
  • Focal Visual Pathway: Seeing detail, clarity.
  • Convergence: Eyes move inward to close on a target.  Associated with extension and “tightness.”
  • Divergence: Eyes move away from each other to watch a target move far away. If excessive, reflects system instability; possibly hypermobility somewhere.

Visual Goals

In PRI Vision-land, the goal is to maximize space and centering to establish alternating and reciprocal activity. You could also call this gait.

When our brain drives us into a right lateralized pattern, typically our eyes accommodate to best perceive the environment. The left eye becomes more focal, and the right eye likes to be more ambient.  This unilateral functioning leads to less left-sided visual space perception.

If I do not need to perceive as much space, this could reflect positioning of the rest of the body. I do not need as many planes or positions to move in when I have less environment to survive in. If I become myopic and only need a small space to live in, I will extend because I only need the sagittal plane to survive in that confined space.

The brain wants visual space and kinesthetic input to match, and will make the necessary accommodations for that to occur. These accommodations at the neck in particular include right upper cervical sidebending and left lower cervical rotation.

To maximize space, the goal would be to reverse the function of the eyes. How do we do that? A simple way, like all other PRI techniques, we drive someone left.

Ron simply demonstrated this change by improving passive hip abduction by 30-degrees after educating a classmate just to become aware of her left hand. He maximized her left space.

Take away: Become more aware of objects on the left side. Learn to love the left environment

We also want our folks to be able to center. This concept reflects a balance between top-down and bottom-up influences on position.  Basically, we want to be able to maximize support from the floor while using appropriate visual perception.

In one who is first neutral, the eyes have to move independently of the head and neck in left stance. If one leans or lists, barring potential below-neck impairments have been addressed, then they are likely either using the visual system to hold themselves upright or have a vestibular problem.

Heads, Bodies, and Necks  (Oh My)

Many of the above concepts occur by differentiating eye, head, neck, and body movements. Ron and Heidi discussed many different reaction types to illustrate vision’s connection to other body movements.

Head on Body Righting Reaction (HOB) – The goal is to be able to have the head and neck move independently of the body. If limited, head and neck have limited mobility in right side bending, flexion, and left rotation.  The head, neck, and body move as one unit.

Neck on Body Righting Reaction (NOB) – Turn the neck and the body follows. This is a primitive reflex that ought to drop off around the age of three. If not, then the neck is running the body’s position.

Body on Head Righting Reaction (BOH) – Turn the body and the head follows, indicating feet have no input into body righting.  The neck matches the body in terms of rigidity and extension.

Body on Body Righting Reactions (BOB): The body has the capacity to regulate itself with contact from the ground and without HOB or BOH reliance.

In PRI Vision, we want to maximize HOB and BOB to the best of our capacity.  We want to take ascending input from the body and react without descending reliance from the head and neck.

Visual Neutrality

To constitute the visual system being neutral, we need to develop the following qualities:

  • The right eye needs increased focal dominance.
  • The left eye needs more peripheral vision.
  • A not too excessive astigmatism correction.
  • Accurate binocular alignment at distance (both eyes working together); with the capacity to tolerate slight changes in convergence/divergence.
  • Flexibility between seeing close and far.

The flexibility to see close and far actually ties to a very huge PRI concept, the ZOA. This time, however, we are not talking about a zone of apposition. We are talking about the Zone of Asymptote.

Those not familiar with an asymptote, we are dealing with this picture below.


Neutrality not only of the visual system, but the entire human system, runs in this fashion. We never truly reach total neutrality; only approach it [0]. Instead, we alternate between progressive flexion (top right) and extension (bottom left), parasympathetic (top right) and sympathetic (bottom left), depending on what is required to perform a task. Going too far in either direction is when we run into problems.

We can test this neutrality with many of the previous PRI assessments I have outlined. What is new to this course is the upper cervical sidebend (normally limited right), and then a few standing tests to assess some of these reactions in three planes. I won’t go into detail on these tests because they involve visual intervention…and because I can’t do them 🙂


Patients are classified into 3 different levels (1, 2, 3), with each level indicating a progressively more unstable/unpredictable visual system.

Level 1 folks typically present with more basic aches and pains, and have impaired HOB reactions.  Treating these patients requires emphasis on visual accommodation by altering the space they perceive.  This training will allow for vision that does not require cervical stability.

Level 2 may have scoliosis or whiplash, and dizziness-symptoms. These folks usually have some instability somewhere in the system.  These patients would be considered NOB.  Treatment emphasizes sensory and proprioceptive accommodation by finding and feeling reference centers on a stable visual system.

Level 3 patients typically have a history of head trauma or spine/eye surgery. These patients need to maximize both visual and sensory accommodation, as well as be able to alternate between the two.  These patients must maximize both bottom-up and top-down inputs.

To a certain extent therapists and other clinicians can affect the visual system, but this depends on how far along the pattern one is. If too far, an optometrist will likely need to be involved.  These patients have failed to become fully neutral by all other PRI interventions.

With an optometrist providing the visual references, the clinician takes the patient through three training phases.

Each phase progressively challenges the interaction among the visual system, body, and environment.  A lot of the training involves simple daily reminders such as maximizing peripheral vision, planting feet when turning head, not looking at the ground, physical activity with PRI glasses on, focusing on arm swing, etc.

I also picked up a couple exercises that I think could be beneficial regardless of a visual problem.  The first activity helps develop HOB reactions by differentiating eye and head movement.

 The next exercise is an excellent technique for helping someone feel the ground. This goal can be met by creating less ground to contact via a narrow board.

 Conclusive Pearls for the Girls

Just like all other systems, the visual system naturally tends toward a certain asymmetry that many of us must battle against to maximize triplanar movement and autonomic balance. 

The biggest pickup from this class was the need for interdisciplinary care. I sometimes fall into a pattern in which I think I should be able to provide the necessary skills to help just about everyone, but PRI Vision gave me a reality check.

We can only help someone insofar as are scope and skill-set allows. Perhaps there shall be a day where having multiple disciplines working in the same room with someone will be the norm.

Until then, I’ll be looking to make friends with an optometrist.

Other Random Factoids

  • Infants only see black and white; therefore good developmental toys should only be black and white.
  • Vision is guided by gross motor until age 4, then vision guides gross motor. If a child works predominately on screens at this age, they miss out on manipulating space because screens are only 2-dimensional. Could possibly affect visuomotor output.

Very Wise Heidi quotes

  • “Just because you have it [vision] doesn’t mean you use it like you could.”
  • “The path of least resistance for the brain is the pattern.”
  • “The position you are in is determined by the space your brain thinks you are in.”
  • “The brain tells what the eyes to look for.”
  • “Vision is more than sight, it’s a system.”

In(famous) Ron Quotes

  • [To me as I clicked my pen] “Please don’t tweet that.”
  • “Humans are pretty cool.”
  • “It’s not me who is the problem. It’s the environment.”
  • “Near-sightedness is a disease.”
  • “You can develop strength very well if you keep yourself limited.”
  • “The biggest adjustor to your illusions is your neck. Your neck is your identity.”
  • “The brain selects what it wants to see based on patterns.”
  • “The brain tells your eyes what to do. The eye is the conduit to the soul.”
  • “The eye is the biggest diaphragm you’ll ever have.”
  • “If there is a muscle spindle the autonomic nervous system is involved.”
  • “A rehab setting is the basketball court.”
  • “You all have a form of chiari syndrome.”
  • “If you use your neck your primitive reflexes are still on.”
  • “I think we killed that.”
  • “You right AF IR alwaysbes. You left AF IR wannabes. “
  • “I’d rather have you leave on the right side than confused.”
  • “How does it feel knowing the optometrist in the room is turning muscle on faster than any E-Stim unit?”
  • “Giving someone monovision is the most horrible thing someone can do.”
  • “Idiopathic scoliosis is autonomics. Tweet that.”
  • “We were meant to get bumped and bruised.”
  • “The best Pilates instructor you ever had was a primitive reflex.”
  • “Am I doing this for Medicare reimbursement? Bleh.”
  • “Put a contact lens on your left butt.”
  • “You weren’t meant to be on this Earth to be facilitated. You were meant to be on this Earth to be inhibited. That’s what laws are for. Tweet  that. Personally, I’m here to tweet you!.”
  • “If you fail, you treat your patient.”
  • “We spend more time defending than we do treating.”
  • “We all have natural limitations.  They’re called labrums.”


  1. Thanks for your blog Zac….just as I thought I was burnt out…not on patients…but rather on healthcare – you came along…a whole new way of thinking about things…I love it!


  2. Hi Zac

    Just a few questions on the “How we do this” section of vision integration for the baseball player. When picking 3 objects at various distances, is it about keeping these in sight while moving your eyes, or keeping those things in sight and alternating looking at each one?

    I have been through the PRIME program myself, and would love to pick your brain on how you have integrated it with sport in more detail

    1. Hey Shayne,

      Thank you so much for your readership and comment.

      You alternate looking at each object, not necessarily try to look at all at the same time.