Appendix D

Helping Parents Make Decisions About Vision Therapy and Neuro-optometry

Deborah Orel-Bixler

Vision is the dominant sense, and it is accepted wisdom that 80% of what we learn is through vision (Aitken, 2010). Vision is composed of three areas of function:

When children have difficulty in school, whether it is trouble seeing the blackboard or learning to read, teachers and parents may assume these children have vision problems. A comprehensive vision examination should be done to determine if a child simply requires spectacles or requires further evaluation. A routine eye examination should include testing and/ or observation of the following basic visual abilities and eye assessments:

It is important to rule out whether a child who struggles in school simply needs glasses for myopia (nearsightedness), hyperopia (farsightedness), and/or astigmatism (an imbalance in the focus of the eye in all directions). Similarly, a child with visual impairment or low vision may not be able to “see” educational materials. However, other vision problems, besides refractive error and low vision, have the potential to affect academic and reading performance. These are learning related vision problems. A child who struggles in school may have a specific learning disability, a learning related vision problem, or both. If there are concerns about a child’s performance in school, the best way to find out the underlying cause (or causes) of the problem is through a team approach. Team members may include the child’s teachers, the school psychologist, an eye doctor who specializes in children’s vision and learning related vision problems, and perhaps other professionals (American Optometric Association [AOA], 1985).

What are learning related vision problems?

Learning related vision problems represent deficits in two broad visual system components: visual efficiency and visual information processing. Visual efficiency comprises the basic visual physiological processes of visual acuity, refractive error, accommodation, vergence, and ocular motility. Visual information processing involves higher brain functions including the non-motor aspects of visual perception and cognition, and their integration with motor, auditory, language, and attention systems (Scheiman & Rouse, 1994).

What is vision therapy?

Vision therapy is a program of visual activities designed to correct certain vision problems that cannot be treated successfully with glasses, contact lenses, and/or surgery alone. Vision therapy, also known as vision training or VT, is a group of techniques designed to improve binocular vision (ability to use the eyes together as a team), and correct oculomotor disorders (eye movement disorders) and visual information processing disorders (Hoffman, 1988). Vision therapy, in its origins, was known as “orthoptics,” and was introduced in the late 19th century for the non-surgical treatment of strabismus (misaligned eyes). Today, orthoptics is one type of vision therapy often used as an adjunct therapy before and after surgery for strabismus to increase the likelihood of a successful outcome (Shainberg, 2010). Vision therapy has expanded into the treatment of deficits in eye coordination, and dysfunction in accommodation (focusing), perception, tracking, and motor skills. The expansion of vision therapy into these other areas has sparked intense debate amongst eye care professionals (Bowan, 2002; Rawstron, Burley, & Elder, 2005).

Which eye care professional performs vision therapy?

The AOA (2005) defines “doctors of optometry” in the following way:

Doctors of optometry (ODs) are the primary health care professionals for the eye. Optometrists examine, diagnose, treat, and manage diseases, injuries, and disorders of the visual system, the eye, and associated structures as well as identify related systemic conditions affecting the eye. (para. 1)

The educational and clinical background of ODs is composed of many components (U.S. Bureau of Labor Statistics, U.S. Department of Labor, 2010):

The Doctor of Optometry degree requires the completion of a 4-year program at an accredited school of optometry, preceded by at least 3 years of preoptometric study at an accredited college or university. All States require optometrists to be licensed. (p. 372)

The primary U.S. optometric professional organizations include the American Academy of Optometry (AAO) and the American Optometric Association (AOA). A small subset of optometrists are practitioners in behavioral optometry (or developmental optometry). They emphasize the influence of environment and experience on visual function, the relationship of vision to other aspects of behavior, and the role of vision as a modality to gather and process information (Birnbaum, 1994). The professional organizations associated with behavioral optometry include the College of Optometrists in Vision Development (COVD) and the Optometric Extension Program (OEP).

The AAO describes ophthalmologists as “medical and osteopathic physicians who provide comprehensive eye care, including medical, surgical and optical care” (2012, para. 1). Ophthalmologists’ education comprises an undergraduate college degree, 4 years of medical school, a 1-year internship, and at least 3 years of residency in ophthalmology. During residency, ophthalmologists specialize mostly in eye surgery, but also in the management and treatment of eye diseases and conditions. Neuro-ophthalmologists are medical doctors who initially specialize in either neurology, ophthalmology, or both, and then complete a subspecialty fellowship training in the complementary field. Neuro-ophthalmologists typically treat diseases of the afferent visual system (most often involving the optic nerve), the efferent visual system (that controls eye movements), or the pupillary reflexes. Pediatric ophthalmologists are primarily involved in eye care for children. The professional organization associated with pediatric ophthalmologists is the American Association for Pediatric Ophthalmology and Strabismus (AAPOS). Ophthalmologists do not perform vision therapy but may employ orthoptists in their clinical practice.

Orthoptists evaluate and treat patients with disorders of the visual system with an emphasis on binocular vision and eye movements (American Orthoptic Council & American Association of Certified Orthoptists, n.d.). Orthoptists can see patients independently under the sponsorship of an ophthalmologist and commonly work in pediatric ophthalmology settings. The majority of their patients are children, but orthoptists also treat adults with neuro-ophthalmic and adult eye muscle disorders (Shainberg, 2010).

What happens during vision therapy?

Vision therapy is a sequence of activities individually prescribed and monitored by the optometrist or orthoptist. It is prescribed only after a comprehensive eye examination has been performed and indicates that vision therapy is an appropriate treatment option. The vision therapy program is individualized to each patient based on the results of standardized tests, the patient’s needs, and the patient’s signs and symptoms. An integral part of vision therapy is the use of lenses, prisms, filters, occluders, specialized instruments, and computerized training programs (Scheiman & Wick, 1994).

Vision therapy is administered in the office under the guidance of the optometrist or orthoptist. It requires a number of office visits. Depending on the severity of the diagnosed conditions, the length of the program typically ranges from several weeks to several months. Activities similar to in-office techniques are typically taught to the patient to practice at home and reinforce the developing visual skills. The goals of a prescribed vision therapy treatment regimen are to achieve the desired visual outcomes, alleviate the signs and symptoms, meet the patient’s needs, and improve the patient’s quality of life (AOA, 1985).

What does research say about the effectiveness of vision therapy?

Research (AOA, 1985; Scheiman & Wick, 1994; Scheiman et al., 2005) demonstrates that vision therapy is an effective treatment option for the following conditions:

  • Ocular motility dysfunctions (eye movement disorders)
  • Strabismus (misalignment of the eyes)
  • Non-strabismic binocular disorders (inefficient eye teaming)
  • Amblyopia (poorly developed vision)
  • Accommodative disorders (focusing problems)
  • Visual information processing disorders, including visual-motor integration and integration with other sensory modalities

What does research say about behavioral optometry approaches?

In 2000, the United Kingdom’s College of Optometrists commissioned a report to critically evaluate the theory and practice of behavioral optometry. The report concluded that there was a lack of controlled clinical trials to support behavioral management strategies (Jennings, 2000). In 2009, another report was commissioned to evaluate the evidence in support of behavioral approaches as it stood in 2008 (Barrett, 2009). The available evidence was reviewed under 10 headings, selected because they represent patient groups/conditions that behavioral optometrists treat, or because they represent approaches to treatment that have been advocated in the behavioral literature. The headings selected were the following:

  1. vision therapy for accommodation/vergence disorders
  2. the underachieving child
  3. prisms for near binocular disorders and for producing postural change
  4. near point stress and low-plus prescriptions
  5. use of low-plus lenses at near to slow the progression of myopia
  6. therapy to reduce myopia
  7. behavioral approaches to the treatment of strabismus and amblyopia
  8. training central and peripheral awareness and syntonics (phototherapy)
  9. sports vision therapy
  10. neurological disorders and neuro-rehabilitation after trauma/stroke

The report noted that there is a paucity of controlled trials in the literature to support behavioral optometry approaches. Although there are areas where the available evidence is consistent with claims made by behavioral optometrists (most notably in relation to the treatment of convergence insufficiency, the use of yoked prisms in neurological patients, and in vision rehabilitation after brain disease/injury), a large majority of behavioral management approaches are not evidence-based, and thus cannot be advocated (Barrett, 2009).

Does vision therapy treat learning disabilities?

Vision therapy does not treat learning disabilities or dyslexia directly (Hoffman, 1988). Rather, vision therapy is a treatment to improve visual efficiency and visual processing; thereby it allows the person to be more responsive to educational instruction (Solan, 1990). Vision therapy does not preclude any other form of treatment and should be a part of a multidisciplinary approach to learning disabilities (Hoffman, 1988).

In the “Optometric Clinical Practice Guideline,” which represents the AOA, the AAO, and the COVD (AOA, 2008), learning to read and reading for information require efficient visual abilities. The eyes must team precisely, focus clearly, and track quickly and accurately across the page. These processes must be coordinated with the perceptual and memory aspects of vision, which in turn must combine with linguistic processing for comprehension. To provide reliable information, this must occur with precise timing. Inefficient or poorly developed vision requires individuals to divide their attention between the task and the involved visual abilities. Some individuals have symptoms such as headaches, fatigue, eyestrain, errors, loss of place, and difficulty sustaining attention. Others may have an absence of symptoms because of the avoidance of visually demanding tasks. There is a positive correlation between certain binocular anomalies and reading problems (Simons & Grisham, 1987).

The clinical practice guideline concludes that vision problems can and often do interfere with learning. The goal of optometric intervention is to improve visual function and alleviate associated signs and symptoms. Prompt remediation of learning-related vision problems enhances the ability of children and adults to perform to their full potential. People with learning problems require help from many disciplines to meet the learning challenges they face. Optometric involvement constitutes one aspect of the multidisciplinary management approach (AOA, 2008).

Is vision therapy appropriate for children/adults with traumatic brain injury?

Several vision disturbances may occur following traumatic brain injury (TBI) as reviewed by Kapoor and Ciuffreda (2002). These include anomalies (difficulty) with the following:

  1. accommodation (focusing effort for near)
  2. versions (moving the eyes together in all fields of gaze)
  3. vergence (moving the eyes inwards and outwards with near and distance viewing)
  4. photosensitivity (bothered by light)
  5. visual field integrity (extent of peripheral vision)
  6. ocular health

Certain conditions in patients with TBI are either monitored by or referred to neuro-ophthalmologists and ophthalmologists for evaluation and possible surgical or medical intervention. These include non-comitant strabismic anomalies (eye misalignment that changes in different fields of gaze), complex diplopia (double vision) patterns, and advanced ocular health anomalies. Other conditions in patients with TBI are amenable to rehabilitative interventions, such as vision therapy, which is administered by optometrists. These include anomalies of accommodation, vergence, versions, photosensitivity, and field of vision. Vision therapy may be performed alone or along with the prescription of special types of spectacles (eyeglasses):

  1. fusional prism spectacles (for diplopia)
  2. tinted spectacles (for photosensitivity)
  3. yoked prism spectacles (for visual field defects or inattention)

Rehabilitative optometric intervention is appropriate and beneficial for many patients with TBI. For more information on TBI, see Appendix D.

Is vision therapy for visual processing problems appropriate for children with visual impairment or blindness?

The effect of ocular abnormalities on the quality of the visual information available to processing should be carefully evaluated before one assesses the processing of visual information (Hyvärinen, 2010). Children with visual impairment may have deficits in visual acuity, contrast sensitivity, color vision, motion perception, visual adaptation to change in luminance levels, and visual field. Adaptation of educational and testing materials, such as increasing print size and contrast may partially compensate for impairment in these vision functions.

As Hyvärinen (2010) states, many ophthalmologists oppose assessment of visual processing problems, and defer this time consuming task to pediatric neurologists or neuropsychologists. However, the neuropsychological tests for visual processing assume:

  • there is sufficient quality of the incoming information,
  • the encoding of incoming information in the primary visual cortex is normal, and
  • the child has had normal visual experiences before the low vision.

In infants and children who have visual impairments, none of these three prerequisites is usually met. At present, tests in neuropsychology need to be redesigned for testing children with changes in the quality of incoming information and/or processing in the visual cortices.

Hyvärinen (2010) lists the following as early signs of problems in visual processing in infants and toddlers:

  • oculomotor problems, especially convergence insufficiency and exotropia;
  • poor accommodation (especially in hypotonic children with motor problems or Down syndrome) with problems in visual communication and interaction;
  • looking past the face of the adult (tester or parent, ‘poor eye contact’) owing to eccentric fixation because of central scotoma;
  • delay in recognizing family members before they say something;
  • difficulties in communication with other toddlers (owing to loss or difficulties in recognition of faces, facial expressions, body language) and clinging to adults;
  • panic reactions to animals (dogs) and fast-moving objects;
  • problems in using toys if they are cluttered or on a patterned background; and
  • delays in dressing; not knowing which way clothes should be put on. (p. 278)

Preferably, the assessment of infants and children with visual impairments for early intervention and educational services will include a multidisciplinary team. Optometrists and ophthalmologists determine the cause and degree of visual dysfunction. It is desirable to assess visual functioning in four main domains: communication and interaction, orientation and moving, activities of daily life, and use of vision in sustained vision tasks demanding near vision tasks. Results of the assessment need to be explained to parents with reports for teachers and therapists. Special teachers and therapists for visual impairment apply basic evaluations of visual function as part of their work (Buultjens, Hyvärinen, Walthes, & Dutton, 2010).

Is vision therapy for visual processing appropriate for children with cerebral visual impairment?

Cerebral visual impairment (CVI) is the most common cause of visual impairment in children in developed countries. CVI results from damage to the part(s) of the brain involved in vision, and includes subcortical damage. The occipital lobes of the brain process visual information (visual acuity, color and contrast perception, visual field and perception of movement). Higher visual processing takes place in brain areas adjacent to the occipital lobes. The two functional pathways central to this process are the dorsal and ventral streams. The dorsal stream integrates occipital and posterior parietal lobes function (to analyze the visual scene and guide body movement). The ventral stream integrates occipital and temporal lobes function (to serve visual recognition and memory of what is being looked at, and route finding). Brain damage can affect any part of this overall visual system. Children with CVI show visual symptoms consistent with both dorsal stream and ventral stream dysfunction (Dutton, 2010b).

Dutton et al. (2010a) reported that a structured history-taking of visual difficulties can reveal the pattern of visual disability in children with CVI. This is indispensable both in identifying perceptual and cognitive visual dysfunction, and understanding the wide range of day-to-day difficulties experienced by affected children. The information can help guide the custom design of appropriate educational and habilitative strategies for each child (Buultjens et al., 2010). The questions developed by Dutton et al. (2010a), seek evidence of the following:

  • visual field impairment or impaired visual attention on one side;
  • impaired perception of movement;
  • difficulty handling the complexity of a visual scene (dorsal stream dysfunction);
  • impairment of visually guided movement of the body (dorsal stream dysfunction) and further evidence of visual field impairment;
  • impaired visual attention (dorsal stream dysfunction);
  • behavioural difficulties associated with crowded environments; and
  • the ability to recognize what is being looked at and to navigate by means of visual recognition (ventral stream dysfunction). (p. 123)

Dutton (2010a) concludes that further research is required to develop and define optimal clinical questioning strategies that both assist diagnosis and provide useful information to guide management. For more information on CVI, see Appendices B and C.

What is neuro-optometry?

Neuro-optometry, as originally described by Stark, Bahill, Ciuffreda, Kenyon, and Phillips (1977), was an evolving optometry clinical specialty that focused on neurological dysfunctions of the visual system. In the early years, neuro-optometry focused on abnormalities of versional eye movements (the eyes moving together in the same direction) and vergence eye movements (the eyes moving toward each other or apart) and their interaction in achieving fixation, tracking, reading eye movements, and “scanpaths” or free viewing of pictures. The interaction between accommodation, pupillary, and vergence eye movement responses to near and far targets was also studied. More recently, neuro-optometry has become associated with the specialized area of vision therapy to treat people who have suffered traumatic brain injuries (TBI) (head injuries, strokes, etc.). The professional organization associated with neuro-optometry is the Neuro-Optometric Rehabilitation Association (NORA).

Vision dysfunctions are among the most common sequelae associated with acquired brain injury. A significant number of patients with brain injury present with signs and symptoms that indicate a vision problem. These include, but are not limited to, the following: double vision, eye turn, blurred vision, closing or covering one eye, head tilts or turns, reduced ability to sustain attention on visual tasks, bumping into objects, dizziness, difficulty with posture, headaches, balance and coordination problems, eye strain, poor judgment of depth, confusion related to visual tasks, reduced ability to accurately localize objects, and difficulty reading.

Activities of daily living are often impaired in patients with TBI because of the disruption in the integration of visual information processing and visual motor performance (AOA, 1997).

According to the AOA policy statement (1997), the patient with brain injury should be evaluated by an optometrist who has training and clinical experience in the care of eye and vision problems related to brain injury.

As a member of, or consultant to, the patient’s rehabilitation team, the optometrist’s goal is to relate specific visual dysfunctions to the patient’s symptoms and performance in order to provide remediation and guidance. This will increase the effectiveness of the overall rehabilitation program, which is often highly dependent upon vision. Per the AOA (1997), the evaluation of the patient with brain injury may include, but is not limited to, the following:

  • Comprehensive eye and vision examination
  • Extended sensorimotor evaluation
  • Higher cerebral function assessment of visual information processing
  • Low vision evaluation
  • Extended visual field evaluation
  • Electrodiagnostic testing

Optometric management of the patient with brain injury may incorporate any of the following:

  • Treatment of ocular disease or injury either directly or by co-management with other health care professionals
  • Treatment of the visual dysfunction utilizing lenses, prisms, occlusion, low vision devices, and/or optometric vision therapy
  • Counseling and education of patient, family, or caregiver about the patient’s visual problems, functional implications, goals, prognosis, and management options
  • Consultation with other professionals involved in the rehabilitation and health care of the patient. (p. 2)

Optometrists provide essential vision services in the rehabilitation process of the patient with brain injury, including diagnosis, treatment, and consultation in order to maximize the patient’s outcome. The ultimate goal of these services is to improve the patient’s quality of life. (AOA, 1997, p. 2)

References

Aitken, S. (2010). Strategies to help children who have both visual and hearing impairments. In G. N. Dutton & M. Bax (Eds.), Visual impairment in children due to damage to the brain (pp. 245-256). London: Mac Keith Press.

American Academy of Optometry, & American Optometric Association. (1999). Vision therapy: Information for health care and other allied professionals. St. Louis, MO: Author. Available from http://www.covd.org/?page=Position_Papers

American Academy of Ophthalmology. (2012). The American Academy of Ophthalmology: For ophthalmologists; For patients and the public. Retrieved from http://www.aao.org

American Optometric Association. (1985). Position statement on vision therapy. Journal of the American Optometric Association, 56, 782-783.

American Optometric Association. (1997). Optometric care of the patient with acquired brain injury. St. Louis, MO: Author. Retrieved from http://www.aoa.org/documents/Acquired-Brain-Injury.pdf

American Optometric Association. (2005). What is a doctor of optometry? Retrieved from http://www.aoa.org/x4891.xml

American Optometric Association. (2008). Optometric clinical practice guideline: Care of the patient with learning related vision problems. St. Louis, MO: Author. Retrieved from http://www.aoa.org/documents/CPG-20.pdf

American Orthoptic Council, & American Association of Certified Orthoptists. (n.d.). What is orthoptics? Retrieved from http://www.orthoptics.org

Barrett, B. T. (2009). A critical evaluation of the evidence supporting the practice of behavioural vision therapy. Ophthalmic & Physiological Optics, 29, 4-25.

Birnbaum, M. H. (1994). Behavioral optometry: A historical perspective. Journal of the American Optometric Association, 65, 255-264.

Bowan, M. D. (2002). Learning disabilities, dyslexia, and vision: A subject review—A rebuttal, literature review, and commentary. Optometry, 73, 553-575.

Buultjens, M., Hyvärinen, L., Walthes, R., & Dutton, G. N. (2010). Strategies to support the development and learning of children with cerebral visual impairment at home and at school: Communication, orientation and mobility. In G. N. Dutton & M. Bax (Eds.), Visual impairment in children due to damage to the brain (pp. 227-235). London: Mac Keith Press.

Dutton, G. N. (with Calvert, J., Ibrahim, H., Macdonald, E., McCulloch, D. L., Macintyre-Beon, C., & Spowart, K. M.). (2010a). Structured clinical history-taking for cognitive and perceptual visual dysfunction and for profound visual disabilities due to damage to the brain in children. In G. N. Dutton & M. Bax (Eds.), Visual impairment in children due to damage to the brain (pp. 117-128). London: Mac Keith Press.

Dutton, G. N. (with Cockburn, D., McDaid, G., & Macdonald, E.). (2010b). Practical approaches for the management of visual problems due to cerebral visual impairment. In G. N. Dutton & M. Bax (Eds.), Visual impairment in children due to damage to the brain (pp. 217-226). London: Mac Keith Press.

Hoffman, L. G. (1988). The purpose and role of vision therapy. Journal of Optometric Vision Development, 19, 1-2.

Hyvärinen, L. (2010). Classification of visual functioning and disability in children with visual processing disorders. In G. N. Dutton & M. Bax (Eds.), Visual impairment in children due to damage to the brain (pp. 265-281). London: Mac Keith Press.

Jennings, A. J. (2000). Behavioural optometry: A critical review. Optometry in Practice, 1, 67-78.

Kapoor, N., & Ciuffreda, K. J., (2002). Vision disturbances following traumatic brain injury. Current Treatment Options in Neurology, 4, 271-280.

Rawstron, J. A., Burley, C. D., & Elder, M. J. (2005). A systematic review of the applicability and efficacy of eye exercises. Journal of Pediatric Ophthalmology and Strabismus, 42, 82-88.

Scheiman, M. M., & Rouse, M. W. (1994). Optometric management of learning-related vision problems. St. Louis, MO: Mosby-Year Book, Inc.

Scheiman, M., & Wick, B. (1994). Clinical management of binocular vision: Heterophoric, accommodative, and eye movement disorders. Philadelphia: Lippincott.

Scheiman, M., Mitchell, G. L., Cotter, S., Cooper, J., Kulp, M., Rouse, M., … Wensveen, J. (2005). A randomized clinical trial of treatments for convergence insufficiency in children. Archives of Ophthalmology, 123, 14-24. doi:10.1001/archopht.123.1.14. PMID 15642806

Shainberg, M. J. (2010). Vision therapy and orthoptics. American Orthoptic Journal, 60, 28-32. doi:10.3368/aoj.60.1.28

Simons, H. D., & Grisham, J. D. (1987). Binocular anomalies and reading problems. Journal of the American Optometric Association, 58, 578-587.

Solan, H. A. (1990). Learning disabilities. In A. A. Rosenbloom & M. W. Morgan (Eds.), Principles and practice of pediatric optometry (pp. 486-517). Philadelphia: Lippincott.

Stark, L., Bahill, A. T., Ciuffreda, K. J., Kenyon, R. V., & Phillips, S. (1977). Neuro-optometry: An evolving specialty clinic. American Journal of Optometry & Physiological Optics, 54, 85-96.

U.S. Bureau of Labor Statistics, U.S. Department of Labor. (2010). Occupational outlook handbook, 2010-2011 library edition. Washington DC: U.S. Government Printing Office. Retrieved from http://www.bls.gov/oco/reprints/2010-11OOH.zip

Deborah Orel-Bixler, Ph.D., O.D., is a Professor of Clinical Optometry at the University of California, Berkeley, School of Optometry.