NEURO-OPTOMETRIC REHABILITATION:
THE NEXT CHALLENGE
FOR OUR PROFESSION
Diana Eastburn-Ludlam, BS, COVT
William V. Padula, OD, FAAO, FNOR
Vincent Vicci, Jr., OD, PA
Objectives:
1. To develop an understanding of the bimodal visual process and its neurology
2. To create awareness about the visual processing problems following a
neurological event (TBI, CVA, autism, etc.)
3. To develop an understanding about how visual processing disorders affect
performance, function, and binocularity
4. To understand dysfunction of the focal/ambient visual process causing Post
Trauma Vision Syndrome
5. To understand dysfunction of the ambient (spatial) visual process affecting
balance and posture (Visual Midline Shift Syndrome)
6. To explore options of neuro-optometric rehabilitation and the optometrist’s role as
part of the multidisciplinary team
Keywords: brain injury (TBI), cerebrovascular accident (CVA), neurological event,
bimodal visual process (focal/ambient), parvocellular and magnocellular systems,
visual evoked potential (VEP), Post Trauma Vision Syndrome (PTVS), Visual
Midline Shift Syndrome (VMSS), binocular vision, Pusher Syndrome, weight bearing
Neuro-Optometric Rehabilitation:
The Next Challenge for Our Profession
Optometry is a profession that has grown and changed in scope and application at
an unusually rapid rate. In the past century we have moved from simply placing
compensatory lenses in front of individuals no longer able to see detail at a distance or
near to the application of lenses to relieve Asthenopic and devices to enhance lost field
function, to name several. Stepping even further into improving quality of life for
individuals seeking our help, we began using specific lenses, prisms, and specific
therapies to address binocular dysfunction and learning issues.
Improving and developing technology has allowed the health care professions to
glimpse inside the “black box” to begin to assess the cortical processes of the sensory
systems. We can now assess the process of vision and visually acquired information
electro physiologically enabling the optometric physician to evaluate quality, integration,
and potential of the visual system on a neurophysiological basis.
We are now able to monitor the cortical process as it changes by the application
of lenses and prisms. This is of particular interest for individuals who have suffered head
trauma or are living with progressive neurological disorders (multiple sclerosis,
Parkinson’s, etc.) The human visual system is intricately designed and elegantly balanced
and can be rendered functionally invalid often without detriment of correctable acuity.
This can be the result of trauma (physical and/or emotional), progressive neurological
disorder and/or a combination of these conditions.
The challenge and new frontier for the profession is now to use the already
defined characteristics that describe Post Trauma Vision Syndrome and apply the
considerable body of knowledge existing in the use of prisms, lenses, and specific
therapeutic procedures to alleviate the symptoms associated with this syndrome.
To accomplish this goal demands a multidisciplinary effort. The ideal team
consists of Physiatry, Neurology, Occupational Therapy, Physical Therapy, and NeuroOptometry, to name several. This introductory course is intended to begin to address the
challenge and define some of the parameters.
Some of you knew my late husband, William Ludlam. In knowing him you also
knew his single mindedness and his devotion to this profession. He had an abiding
dedication to pursuing scientific truth and applying that information to the alleviation of
symptoms for individuals suffering symptoms of a visual system out of balance. He was a
teacher, researcher, and scientist, but most importantly to him, a creative tireless
clinician. He shared the vision of Dr. Padula, Dr. Vicci, Dr. Thomas, and others in a list
too long to enumerate here that became the Neuro-Optometric Rehabilitation
Association. It is my honor to introduce this two-hour focus course and to present
Doctors Padula and Vicci.
NEURO-OPTOMETRIC REHABILITATION
MEETING THE VISUAL NEEDS OF NEUROLOGICALLY CHALLENGED
PERSONS
WILLIAM V. PADULA, OD, FAAO, FNORA
Within the United States, there are over forty million persons with a neurological
dysfunction. These include persons with traumatic brain injury (TBI), cerebrovascular
accidents (CVA), multiple sclerosis (MS), cerebral palsy (CP), autism, Friedrick’s
Ataxia, and Parkinson’s disease, to name several. The prevalence for neurological
disorders is increasing due to: 1) Advances in medical science enabling more children
to survive premature births and childhood diseases; 2) More persons surviving TBI
due to faster and more advanced life support; 3) An increase in the aging population
yielding CVA, Parkinson’s disease, etc.; 4) And, an increase in autism and pervasive
developmental disorders.
Those who have neurological dysfunction have a high prevalence of vision
difficulties. These may include vision impairment such as hemianopsia and loss of
acuity, however, the majority will have binocular vision problems, and visual spatial
problems affecting posture, balance, and orientation.
Over the past twenty years a new field has emerged in optometry known as NeuroOptometric Rehabilitation. This has occurred because those who are neurologically
challenged often do not have the same needs of persons who are served through low
vision or functional (binocular) vision services. Accompanying vision impairments
and binocular problems are conditions of motor dysfunction (nerve paresis) sensory
imbalances, and cognitive disorganization. There is also growing scientific evidence
that the visual problems caused following a neurological dysfunction or event are due
to cortical and sub cortical processing disorders.
Two primary visual processing systems have been identified called the focal and the
ambient visual process (Trevarthen 1973, Liebowitz and Post 1982). The focal
process is primarily an occipital cortex system and is detail in orientation. The parvocellular system sub-serves the focal process and it receives as well as provides
information from/to higher cognitive perceptual processes.
The ambient visual process is a spatial component of vision which includes but is not
limited to the mango-cellular system. Neurologically, the ambient process is
organized in midbrain by matching information between kinesthetic, proprioceptive
and vestibular processes for the purpose of establishing a spatial context and
reference base from the sensory-motor systems. Once accomplished, this information
is provided by “feed-forward” to the occipital cortex and 99% of the cortex. This
spatial information is relayed from superior colliculus to binocular coordination cells
in order to spatially reference the process of binocular integration. In addition,
through the ambient process spatial reference is established for orientation of the
focal process.
It has been determined that interference with the ambient visual process will affect
the function of the focal system. This can occur from a neurological event such as
TBI, CVA, etc. Even from a whiplash, dysfunction of the ambient process can occur
yielding an imbalance and disassociation between relationship of the focal and
ambient processes.
The disassociation leads to a type of focal binding that has been called Post Trauma
Vision Syndrome (PTVS) (Padula, Argyris, Ray 1994). Research through use of
visual evoked potentials with TBI subjects has documented improvement in the
amplitude in P-100 cross pattern reversal tests by using base-in prism and bi-nasal
occlusion. Additional research has found similar results (Sarno, et al. 2000). It has
been found that PTVS is also associated with specific characteristics of binocular
dysfunction and symptoms (Figure 1) and that these are a correlation of these
characteristics to ambient vision dysfunction.
Neuro-Optometric Rehabilitation is the science and art of diagnosing and treating
dysfunction of the bi-modal visual process following a neurological event affecting
binocularity, balance and posture through use of lenses. Doctors of optometry
practicing this specialty often have rehabilitation hospital privileges and affiliations.
This has led to optometrists being included as part of the interdisciplinary
rehabilitation team and a close working relationship with physiatrists, neurologists,
occupational, physical and speech therapists, psychologists, nurses, etc.
The emerging field of Neuro Optometric Rehabilitation has developed to meet the
visual needs of neurologically challenged persons. Further, Neuro Optometric
Rehabilitation serves as the bridge between current visual-neurological research and
state-of-the-art clinical treatment. Neuro Optometric Rehabilitation provides a unique
framework for studies and research about related visual processing disorders caused
by neurological events and the means to serve these afflicted individuals through noninvasive and often life-changing treatment approaches.
TABLE I
POST TRAUMA VISION SYNDROME
Common Characteristics and Symptoms
Characteristics
Symptoms
Exotropia of High Exophoria
Possible Diplopia
Accommodative Dysfunction
Objects Appear to Move
Convergence Insufficiency
Poor Concentration and Attention
Low Blink Rate
Staring Behavior
Spatial Disorientation
Poor Visual Memory
Poor Fixations and Pursuits
Photophobia (Glare Sensitivity)
Unstable Ambient Vision
Asthenopic Symptoms
Dizziness or “Lightheadedness”
TABLE II
VISUAL MIDLINE SHIFT SYNDROME
Associated Characteristics and Symptoms
Characteristics
Symptoms
Hemiplegia
Floor May Appear Tilted
Hemiparesis
Walls and/or Floor May Appear
to Move
Flexion
Extension
Person Leans Away From Affect
Side
Side Neglect
“Pusher” Syndrome
I. Introduction
A. Demographics
B. Building a Model of Vision to Affect Rehabilitation
II. Neuro-Anatomy
A. Statistics
B. Neurology
1. Central Fibers
2. Lateral geniculate
3. Peripheral Fibers
4. Midbrain
a. Superior Colliculus
5. Spino-tectal Tract
6. Occipital Cortex
III. Vision: The Process
A. Focal Process
1. Occipital Cortex
a. Identification
b. Detail
c. Concentration
d. Attention
B. Ambient Process
1. Spatial Orientation
2. Balance
3. Coordination
4. Movement
5. Anticipation of Change
C. Relationship to Neurology
1. Axons from Lateral Geniculate to Midbrain
2. Sensory-Motor Feedback Loop
3. Magnocellular Fibers
4. Parvocellular Fibers
5. Ambient Vision Neurology
D. New Concept
1. Perception
IV. Post Trauma Vision Syndrome (PTVS)
A. Symptoms
1. Movement of Print when Reading
2. Headaches
3. Eye Strain
4. Diplopia
5. Photophobia
6. Hallucinations
B. Characteristics
1. Exophoria
2. Exotropia
3. Convergence Insufficiency
4. Accommodative Dysfunction
5. Myopia
C. Research
1. Dysfunction of Pursuit Tracking
2. Focusing
3. Convergence
4. Accommodation
5. Refraction
V. Visual Midline Shift Syndrome
A. Visual Midline Test
B. Compromise of the Ambient Visual Process
C. Relationship to Posture and Balance
D. Symptoms
1. Seeing Movement in Peripheral Vision
2. Seeing Floor Tilted or Distorted
E. Characteristics
1. Leaning to Side
2. Hemiparesis or Hemiplegia
3. Paradoxal Visual Midline Shift
F. Treatment
1. Use of Yoked Prisms/Affect on Wheelchair Positioning
VI. Therapeutic Intervention for Persons with Post Trauma Vision Syndrome and
Visual Midline Shift Syndrome
VII. Conclusion