NOR is a sub-specialty of optometry that recognizes the crucial role of vision in human performance. A Neuro-Optometrist evaluates the visual process from a functional standpoint, that is, how vision dysfunction is affecting activities of daily living. Special emphasis is directed toward evaluating visual-motor, visual perceptual, and visual information processing dysfunction in the neurologically affected person. Neuro-Optometrists are highly trained professionals uniquely skilled and experienced in the technologies of Neuro-Optometric habilitation / rehabilitation of the persons affected by:
- Acquired Brain Injury (ABI)
- Traumatic Brain Injury
- Penetrating Injury
- Stroke / Aneurysm
- Brain Surgery
- Whiplash
- Concussion
- Anoxic Injury
- Drowning
- Severe Blood Loss / Anemia / Oxygen Deprivation
- Chemical Injury
- Infectious Injury
- Neuro-Developmental Disorders
- Cerebral Palsy
- Spina Bifida
- Congenital Ataxia
- Autism Spectrum Disorders
- ADD / ADHD
- PDD
- Asperger’s
- Autism
- Fragile X
- Fetal Alcohol Syndrome
- Other
- Neuro-Degenerative Disorders
- Multiple Sclerosis
- Parkinson’s
- Alzheimer’s
- Others
Integration of unique Neuro-Optometric treatment modalities within in the rehab team maximizes the patient’s rehabilitative outcome.
Vision, as defined by the Neuro-Optometrist, is how one uses visual sensory input to guide and direct all action, including integrating visual sensory input with memory and all other sensory systems (proprioception, kinesthetic, tactile, vestibular, auditory) to accomplish all activities of daily living. Research estimates that 80-85% of our perception, learning, cognition, and motor activities are mediated through Vision.
Patients suffering from Acquired Brain Injury (ABI), Neuro-Developmental or Neuro-Degenerative Disorders commonly have various Functional Vision Problems leading to decreased performance of Activities of Daily Living (ADL’s). Patients will not be able to achieve maximum rehabilitative potential unless these visual process dysfunctions are addressed with proper Neuro-Optometric Rehabilitation (NOR).
Optometric Rehabilitation Evaluation is unique because, in addition to a traditional ophthalmological evaluation of sight, basic binocular visual skills, and ocular health, it places the patient into performance testing to determine how the visual process is interacting with other sensory feedback mechanisms. Visual information processing is also evaluated as it relates to vocational and avocational tasks.
Dangerous, Functional Vision problems commonly found in the ABI population include:
These Vision problems are not typically evaluated in a regular ophthalmological evaluation, but must be evaluated by a doctor specializing in functional vision rehabilitation. These Vision problems are the most disabling and increase dependency and risk of secondary injury unless addressed properly.
Unique functional testing protocols with unique equipment are used during the NOR evaluation process, which frequently takes 2-3 hours. Insight of how the patient is using vision to accomplish ADL’s is then used to formulate a comprehensive treatment plan. NOR Treatment Plans may utilize any or all of the following: lenses, prisms (both compensatory and therapeutic), filters, selective or full occlusion, vision rehabilitation therapy, primitive motor reintegration therapy, counseling, orientation and mobility training, low vision aids, nutrition, surgery, treatment of ocular pathology, and coordination of care with other professionals on the rehab team.
Unique functional Vision tests include:
- Electrodiagnostic Testing:
- Visagraph Infrared Eye Movement Recording
- Visual Evoked Potential
- Extended Binocular Vision Testing
- Visual-Multitasking Testing (simultaneous central / peripheral visual processing)
- The Attention Assessment
- Useful Field of View
- Accuvision or DynaVision
- Primitive Motor Reflex Testing
- Postural and Ambulatory Observation and Testing with and without Yoked Prism or Compensatory Prism, with or without video recording
- Extended Visual Field Testing
- Threshold Testing
- Frequency Doubling Testing
- Amsler Grid Testing
- Kinetic Near Campimetry or Near Form Fields
- Extended Contrast Sensitivity Testing
- Vestibular-Ocular Reflex Testing
- Visual Analysis Skills Testing
- Visual Midline Testing
- Unilateral Spatial Inattention Testing
Some of these valid and useful procedures do not yet have CPT codes for insurance billing purposes and are usually billed as additional special procedures, which are listed as “non-covered” by most insurers and therefore the patient’s financial responsibility.
NEURO-OPTOMETRIC PROCEDURE DESCRIPTIONS
- Extended Binocular Vision Testing: Brain injury often results in an inability to use the two eyes as a team in an efficient manner resulting in double vision, dizziness, eye strain, and/or visual-spatial dysfunction. Multiple measurements of alignment of the two eyes in different positions of gaze, ability to track and change fixation, depth perception, fusion stability, and ability to change focus are necessary to determine the nature of the binocular dysfunction.
- Visual Midline Shift Testing: Sensory feedback from vision, inner ear (vestibular), and position sense of the muscles (kinesthetic) and joints (proprioceptive) is integrated in the midbrain. A certain balance between these sensory systems is gradually established through normal development. This balance is what gives us an awareness of our body position in space and is often disrupted in brain injury. Because vision is the dominant sense it often “pulls” our sense of our position in space to one side. This is called a Visual Midline Shift. Symptoms include drifting to one side while ambulating, excessive leaning forward, backward, or to one side, and difficulty maintaining posture. Testing is accomplished by having the patient report when a wand appears centered in middle of their face as it is passed from one side to the other. The patient’s response is then correlated with their performance on Postural and Ambulatory Observation and Testing.
- Postural, Ambulatory, and Performance Observation and Testing with and without Yoked Prism or Compensatory Prism: Neuro-Optometrists frequently use two kinds of prism in vision rehabilitation. Yoked Prism has the prism base directed in the same direction (ex. base right in front of each eye) and is used to change the perceived position of visual space to counter cortical misperception of true space. Compensatory Prism is generally used to compensate for a misalignment of the eyes or weakness in eye-teaming. The prescribed prism is established by finding the prism that allows the most efficient performance on a number of motor tasks including, eye coordination, hand-eye coordination, and ambulating.
- Primitive Motor Reflex Testing: Primitive reflexes are reflex actions originating in the central nervous system that are exhibited by normal infants but not neurologically intact adults, in response to particular stimuli. These reflexes disappear or are inhibited by the frontal lobes as a child moves through normal child development. Older children and adults with atypical neurology (for instance, people with cerebral palsy) may retain these reflexes, and primitive reflexes may re-appear in adults due to certain neurological conditions including, but not limited to, dementia, traumatic brain injury, and strokes. This is because the balance between sensory input from vision, vestibular, kinesthetic, and proprioception is disrupted by the injury causing a regression to primitive movement patterns.
Retained primitive reflexes will contribute to poor balance / posture / gait, poor spatial awareness, motion sickness, difficulty with figure-ground, sustained attention, sensory defensiveness, anxiety, vigilance toward injury, poor short-term memory, poor hand-eye coordination, and reduction in energy.
Testing is accomplished by having the patient perform specific body movements and observing how they accomplish them. Standardized grading of their performance is compared to normals to determine the extent of integration or dis-integration (retained) of each reflex. A reflex integration program is then designed for the patient’s specific reflex profile. These programs typically involve performing particular body movements daily for a period ranging from 2-9 months depending on the severity.
- Unilateral Spatial Inattention (Neglect) Testing: Brain injury may cause USI. USI is an involuntary, unconscious decreased awareness of part of the field of view or other stimuli to one side of the body. It usually occurs with a visual field defect, but may occur without loss of field. A patient without USI, but with a visual field loss, would still be aware of the area of loss and be more likely to make compensations. A patient with both visual field loss and USI would unconsciously “neglect” the area of the field loss and thus be less likely to compensate for the defect, making them significantly more vulnerable to secondary injury. A number of clinical performance tests are used to determine the presence and severity of USI. Testing correlates level of USI with extent of visual field loss. A treatment plan is developed, which may include the use of yoked prism, field awareness prism, orientation and mobility training, and visual attention stimulating activities.
- Extended Visual Field Testing: Brain injury can damage the visual pathway directly and cause permanent peripheral vision loss. Brain injury can also damage secondary visual pathways, which can exert an inhibitory influence on the visual cortex, causing functional peripheral vision loss. Suppression and USI are types of functional peripheral vision losses. Testing needs to be done that will determine the extent of peripheral vision and differentiate between permanent and functional peripheral vision loss. Functional peripheral visual field loss is amenable to Vision Rehabilitation Therapy. Permanent visual field loss is compensated for by field expansion prisms, mirrors, teaching scanning strategies, and orientation and mobility training, and may be partially amenable to VRT.
Traditional Static Threshold Bowl Perimetry is sensitive to detect both Permanent and Functional field defects but not specific. Therefore, several types of visual field tests are required to correctly diagnose visual field loss and determine the appropriate rehabilitative plan. Several tests may be run on the same day and may include:
- Confrontation Visual Fields: a gross screening of field defects usually done by asking the patient to count the number of fingers presented in each quadrant to each eye
- Static Threshold Perimetry (Humphrey): picks up most field defects
- Frequency Doubling Perimetry: more sensitive for Functional field defects
- Kinetic Near Campimetry: tests for Functional constriction of the visual fields, including sensitivity fields to different colors.
- Visual-Multitasking (simultaneous central / peripheral visual processing) Testing: Sometimes referred to as “divided visual attention”, the ability to simultaneously attend to central and peripheral visual stimuli is often impaired in brain injury, neuro-developmental, and neuro-degenerative dysfunction. As a result the patient habitually views the world with “tubular-like” vision, one thing at a time. Symptoms include reduced multitasking ability, slower speed of processing, accident proneness, poor lane positioning and maintenance while driving, drifting while ambulating, bumping into things, getting lost, anxiety, vigilance, and not aware of surroundings. Testing is accomplished by having the patient perform a cognitive central task while simultaneously responding to visual stimuli in the periphery. Visual Multitasking can be developed / retrained with proper Neuro-Optometric Rehabilitation. Tests include:
- Useful Field of View: http://visualawareness.com/Pages/whatis.html The area from which one can extract visual information in a brief glance without head or eye movement. The limits of this area are reduced by poor vision, difficulty dividing attention and/or ignoring distraction, and slower processing ability
- Accuvision or Dynavision: http://www.dynavision2000.com/productinfo.html The most unique and important contribution of the Dynavision to rehabilitation is its capacity to challenge the peripheral visual system. Peripheral visual attention is needed to protect an individual from potential dangers in the environment, and speed in searching the peripheral visual field is critical to safety in environments involving rapid visual changes such as is encountered in driving. The size of the Dynavision board automatically elicits a combination of head turning and eye movement which is the natural scanning strategy initiated when attending to peripheral visual stimuli. The light buttons also are identical which eliminates the need for discrete identification and instead elicits the more automatic response of visual localization which is compatible with the function of peripheral attention. This capacity enables the Dynavision to challenge the peripheral attention skills needed for driving, and orientation to and negotiation of the environment at a level few clinical activities can achieve.
The Attention Assessment: http://www.scientificdriverassessments.com Vehicle operation presents unique and complex cognitive and visual challenges. The driver must continually be aware of hazards in all parts of the landscape while at the same time dividing attention to different tasks. TAA, therefore, measures an individual’s ability to detect and respond to critical targets in all parts of the visual field under divided-attention and non divided-attention conditions. Often when a drug (or stress) compromises cognitive and/or visual search performance, it results in “visual field narrowing,” or commonly referred to as “tunneling.” TAA is the only test available that measures the nature and extent of tunneling. It does this by calculating the driver’s efficiency in accurately scanning the visual field over and over again. TAA’s ability to document tunneling is used by police driving instructors as a scientific measure of life-threatening reactions during a crisis. |
