Binocular and Accommodative Problems Associated With Learning Problems
This chapter is not designed to provide new diagnostic tests or treatment procedures for vision disorders associated with reading problems. The accommodative, binocular vision, and eye movement disorders associated with reading are identical to those described earlier in this book. Rather, the area of emphasis of this chapter is the unique role of the optometrist in the comanagement of reading-related vision problems.
Comanagement is the key word, and it refers to the fact that, in most cases, to be maximally effective, the optometrist must interact with a number of other professionals when treating patients with reading-related vision problems. This need for comanagement makes this area one of the more challenging aspects of optometric care; to be successful in this role, an optometrist must have an understanding of the following:
Reading dysfunction
The relationship between vision problems and reading dysfunction
Psychoeducational testing used in the diagnosis of reading dysfunction
The objectives of optometric intervention
An understanding of these issues allows the optometrist to ask appropriate questions during the case history interview, relate test findings to the presenting complaints, and make appropriate management decisions.
Role of the Optometrist in the Management of Learning- and Reading-Related Vision Disorders
Optometry has a long history of involvement in the area of vision, and learning and reading.1 Much of this interest has been generated by the concerns of parents and the referrals of teachers, psychologists, and other professionals who often turn to us for answers about whether a child has a vision problem that is contributing to (or responsible for) his/her poor school performance.1,2
In 1997, the American Academy of Optometry and the American Optometric Association published a position statement on vision, learning, and dyslexia.3 This position statement was accepted and approved by all major organizations in the field of optometry. More recently, the American Optometric Association published its clinical practice guidelines on the care of the patient with learning-related vision problems.4 Both of these documents clearly delineate the role of optometry in the diagnosis and treatment of learning-related vision disorders, and emphasize that optometrists do not treat learning or reading problems. The optometrist’s primary role is the diagnosis and treatment of vision problems that may interfere with school performance. “The expectation for intervention should be the reduction or elimination of signs and symptoms associated with the particular visual deficits.”4 Optometrists do not directly treat the reading or learning problem.
The Convergence Insufficiency Treatment Trial (CITT) Investigator group recently completed a large-scale, multicenter randomized clinical trial to determine the effect of office-based vergence/accommodative therapy on reading performance and attention in 9- to 14-year-old children with symptomatic convergence insufficiency in grades 3 through 8. Three hundred ten children, 9 to 14 years, with symptomatic convergence insufficiency were randomized in a 2:1 ratio to office-based vergence/accommodative therapy or office-based placebo therapy, respectively. Measures of reading were assessed at baseline and after 16 weeks of treatment. The primary outcome was change in reading comprehension at the 16-week visit compared with baseline, measured with the Reading Comprehension subtest of the Wechsler Individual Achievement Test, 3rd Edition (WIAT-III). Secondary reading outcomes of interest were word identification, reading fluency, listening comprehension, and comprehension of extended text. Improvement in WIAT-III Reading Comprehension did not differ significantly between the treatment groups. Although there were significant improvements in children signs in the office-based vision therapy
group compared with the placebo group, the adjusted mean improvement in WIAT-III Reading Comprehension was 3.7 standard score points in the office-based vergence/accommodative therapy group and 3.8 points in the office-based placebo therapy group. No statistically significant group differences were found for improvement on any of the secondary reading outcome measures. The authors concluded that for children ages 9 to 14 years of age with symptomatic convergence insufficiency, office-based vergence/accommodative therapy was no more effective than office-based placebo therapy for improving reading performance after 16 weeks of treatment.5 Thus, for most patients, vision therapy by itself should not be expected to directly improve reading performance. Rather, reading and other educational remediation will be required to impact academic performance.
group compared with the placebo group, the adjusted mean improvement in WIAT-III Reading Comprehension was 3.7 standard score points in the office-based vergence/accommodative therapy group and 3.8 points in the office-based placebo therapy group. No statistically significant group differences were found for improvement on any of the secondary reading outcome measures. The authors concluded that for children ages 9 to 14 years of age with symptomatic convergence insufficiency, office-based vergence/accommodative therapy was no more effective than office-based placebo therapy for improving reading performance after 16 weeks of treatment.5 Thus, for most patients, vision therapy by itself should not be expected to directly improve reading performance. Rather, reading and other educational remediation will be required to impact academic performance.
Table 22.1 THREE-COMPONENT MODEL OF VISION | ||||||||
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Therefore, the goals of optometric intervention must be specific and problem-oriented, rather than indefinite, such as “to improve school performance.”4 A key element in this philosophy is the recognition of the multifactorial nature of learning disorders. Children generally need a variety of services, such as educational remediation, psychological counseling, occupational therapy, and speech/language intervention, to deal with the actual learning disorder. Another important concept discussed in these documents, as well as in previous studies and reports,2,6 is that optometrists should conceptualize vision as comprising three interrelated areas (three-component model of vision), as listed in Table 22.1. To adequately identify learning- or reading-related vision problems, all three areas must be fully evaluated.3
We strongly agree with these two essential concepts and believe that vision disorders can contribute to reading difficulties but they are generally not the primary etiologic factor. Rather, vision disorders represent one of the factors that may interfere with an individual’s academic performance and make it difficult for him/her to perform up to his/her potential. To consider the relationship between vision and reading, we will use the model described in Table 22.1. This chapter is not intended to be a complete discussion of all vision problems associated with learning and reading disorders. For example, the topic of visual information processing disorders is not addressed. Readers interested in this topic should refer to other available textbooks.2,7,8,9
Learning and Reading Disabilities: Definition and Epidemiology
In 1987, the Interagency Committee on Learning Disabilities at the National Institutes of Health developed the following definition of learning disabilities10:
Learning disabilities is a generic term that refers to a heterogeneous group of disorders manifested by significant difficulties in the acquisition and use of listening, speaking, reading, writing, reasoning, or mathematical abilities. These disorders are intrinsic to the individual and presumed to be due to central nervous dysfunction. Even though a learning disability may occur concomitantly with other handicapping conditions (e.g., sensory impairment, mental retardation, social and emotional disturbance) or environmental influences (e.g., cultural differences, insufficient or inappropriate instruction, psychogenic factors), it is not the direct result of those conditions or influences.
Solan11 criticized this definition as being ambiguous and not testable, and noted that it is difficult to establish the specific criteria for diagnosing a learning disability from this definition. This is one of the main reasons why it has been nearly impossible to establish the number of people affected by learning disabilities in a particular population.11 Depending on the diagnostic process and the definition used, estimates of the prevalence of learning problems among school-aged children range from 2% to 10%.10,12 Nationally, about 5% of all schoolchildren
are diagnosed with learning disabilities (and an equal or higher number have milder learning problems).4 Of that population, as many as 75% have reading problems.13
are diagnosed with learning disabilities (and an equal or higher number have milder learning problems).4 Of that population, as many as 75% have reading problems.13
The objective of this chapter is to review the management of the most common visual efficiency problems that contribute to the most common learning disorder. Because the most common learning problem is reading dysfunction,4 it is the specific problem addressed in this chapter. We also use a series of cases to demonstrate some of the important concepts discussed in this chapter.
Reading Dysfunction
Failure to learn to read is the most predominant and important subtype of specific learning disability.11 Even after a century of concern, this enigmatic educational problem has eluded solution.11 Part of the difficulty has been confusion and disagreement over definitions and terminology. For the purposes of this chapter, we define reading dysfunction as a failure to learn to read despite average or above average intelligence, adequate or even abundant educational opportunities, normal sensory development (auditory and visual), normal acculturation, no frank brain damage, and no primary emotional disturbance.14 Thus, conditions such as mental retardation, emotional disturbance, educational deprivation, hearing impairment, and visual handicaps are eliminated from being primary determinants.11
Another term commonly used when discussing reading problems is dyslexia. The term is problematic because it can mean different things to different clinicians, leading to considerable confusion in research and clinical care.8 Some clinicians use the term dyslexia as a synonym for reading dysfunction. Most authors believe, however, that it is important to differentiate dyslexia from the more common nonspecific or general form of reading dysfunction described earlier. Griffin and Walton15 suggested that dyslexia may be characterized as a specific type of reading dysfunction in which there is a deficit in an individual’s ability to interpret the symbols of written language because of minimal brain dysfunction or differential brain function. Dyslexia tends to be a more severe form of reading problem, with a poorer prognosis, with the implication that it is due to some type of brain dysfunction.
A neuroanatomic model has been described that identifies three basic types of dyslexia, each with its specific anatomic location.16 The three types of dyslexia are listed in Table 22.2, along with the presumed anatomic location of the brain dysfunction.
The Dyslexia Determination Test15 and the Boder Test of Reading-Spelling Patterns,17 which require about 30 minutes to administer, allow clinicians to determine the specific type of dyslexia. A screening test that requires only 5 minutes, the Dyslexia Screener allows for rapid screening for the three types of dyslexia.18,19
Dyslexia has received substantial publicity in the popular press, and parents may use this term when referring to their child’s reading problem even if dyslexia is not actually present. The prognosis in cases of true dyslexia is guarded; in most cases, even with intervention, the individual never acquires normal reading ability. Fortunately, the majority of reading problems encountered in an optometric practice will be the less serious (more common) form of nonspecific reading dysfunction. With appropriate intervention, these cases have an excellent prognosis.
Relationship between Vision Problems and Reading Dysfunction
Flax1,20 has emphasized the importance of using a task analysis approach when attempting to relate vision disorders to reading dysfunction. He believes that this approach is useful in both understanding patient complaints and, even more important, being able to explain patient behaviors and predict the outcome of optometric intervention.20
Table 22.2 TYPES OF DYSLEXIA | ||||||||||||
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Table 22.3 COMMON PRESENTING COMPLAINTS | ||
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Table 22.4 DEFINING THE NATURE OF THE READING PROBLEM | ||||
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Table 22.3 lists some of the common initial complaints that we hear as optometrists from parents of children who may have nonspecific reading dysfunction. The objective of the case history and task analysis approach is to gain a specific understanding of the nature of the reading disorder.
Flax1 describes two excellent examples of children presenting with a chief complaint of “reading problems with poor comprehension.” We have summarized these two examples in Table 22.4.
To understand the nature of the reading problem faced by a child, Flax1,20 and Borsting and Rouse21 suggest a model that distinguishes between “learning to read” and “reading to learn.” These two phases of reading are summarized in Tables 22.5 and 22.6.
As per this model, it is clear that visual efficiency disorders (accommodative, binocular vision, and eye movement disorders) are most likely to affect reading performance in grades 4 and above when a child is reading to learn.22 In the earlier grades, when children are learning to read, they are not expected to maintain prolonged attention and
concentration on reading; the teacher changes activities frequently; and the print size is large. Of course, it is important to remember that school systems vary in the demands they place on children in different grades. It is critical, therefore, for an optometrist to become aware of the teaching philosophy of the children’s respective school systems in order to understand the reading demands on children presenting in his/her practice with a reading dysfunction.
concentration on reading; the teacher changes activities frequently; and the print size is large. Of course, it is important to remember that school systems vary in the demands they place on children in different grades. It is critical, therefore, for an optometrist to become aware of the teaching philosophy of the children’s respective school systems in order to understand the reading demands on children presenting in his/her practice with a reading dysfunction.
Table 22.5 LEARNING TO READ | ||||
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Table 22.6 READING TO LEARN | ||||
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Table 22.7 SIGNS AND SYMPTOMS ASSOCIATED WITH VISUAL EFFICIENCY PROBLEMS | ||||
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Table 22.7 lists the common signs and symptoms associated with visual efficiency problems and reading.
Research Supporting the Relationship between Visual Efficiency Problems and Reading
Although there has been a considerable amount of literature devoted to determining whether there is a relationship between visual efficiency skills and reading, results have varied significantly from one researcher to another.22 Some investigators have reported a definitive relationship, others suggest that no relationship exists, and a third group believes that there is no definitive proof either way. Garzia23 comments:
Unfortunately this confusion has been malinterpreted to mean that vision and more specifically visual function has a minor role or no role at all in reading achievement. This has been extended to the clinical domain by the general inattention directed to the visual efficiency of children experiencing difficulty learning to read.
Nevertheless, despite some difficulties in research efforts, a credible pattern of association between visual skills and reading ability emerges.23 In an extensive study-by-study narrative review of the literature, Grisham and Simons24,25 concluded that there is a relationship between refractive status and binocular vision and reading. This was further supported by a meta-analysis of the same literature.22
There also appears to be a relationship between eye movements and reading. When the reading eye movement patterns of disabled readers are evaluated, a characteristic pattern emerges. The eye movements of poor readers are characterized by an increased number of forward fixations per line of text, an increased number of regressions, longer fixation durations, and a higher prevalence of intraword scanning, when compared with normal readers.26 Studies by Pavlidis27,28,29 indicate that disabled readers have poor eye movement control. He required his subjects to saccade between a series of sequentially illuminated equidistant targets. The reading-disabled subjects made a significantly higher number of inappropriate eye movements, especially regressions, and had longer and more variable fixations, and longer reaction times, than did matched normal control subjects.
Other visual functions have not been thoroughly investigated, but they also have the potential for adversely influencing reading proficiency. For an intuitive example, accommodative infacility would make it difficult for classroom reading-related activities that require rapid changes in fixation distance from the chalkboard or teacher to the desktop.23 Any vision assessment of a child having learning difficulty must include not only tests of visual acuity and refractive status but also tests of near point visual skills that are associated with reading. The visual efficiency skills of accommodation, vergence, and ocular motility should be investigated in detail for the presence of any dysfunction that can not only induce visual signs or symptoms but also has the potential for influencing reading achievement.
Colored Filters or Glasses and Reading
Optometrists working with reading-related vision problems invariably encounter questions about the use of colored glasses or filters to treat reading dysfunction. Information about this method of treating reading problems periodically appears in the popular media, and the approach has become accepted by many reading specialists and school systems around the country. It is therefore important for optometrists to be knowledgeable about this treatment approach.
Meares,30 Irlen,31,32 and Wilkins33,34 have described a syndrome of visual symptoms and distortion that can be alleviated with colored filters. This syndrome is referred to as the Meares-Irlen syndrome. Individuals with this condition tend to be ineffective readers who must use more effort and energy when reading because they see the printed page differently from readers who do not suffer from the syndrome. The difficulties individuals suffering from the syndrome experience while reading may include sensitivity to light, eyestrain, difficulty focusing, unstable appearance of the print, distortion of the printed page, words appearing to be moving on the page, and words appearing washed out.32 These problems may lead to fatigue, visual discomfort, and inability to sustain attention as necessary for long periods of time.
Irlen32 claimed that approximately 50% of the reading disability and dyslexic populations have this syndrome and that it is a key factor that interferes with the reading process in these individuals. She suggested that close to 90% of individuals with this disorder can be successfully treated using appropriately tinted lenses called Irlen filters. The objective of her treatment procedure is to eliminate the discomfort associated with reading and to improve reading performance. Irlen32 also suggested that scotopic sensitivity syndrome is a distinct entity that cannot be identified through standardized educational and psychological evaluations, vision examinations, medical checkups, or other standardized diagnostic tests.
Several optometrists35,36,37,38,39,40 have raised concerns about Irlen’s theories and methods. An important issue is the striking similarity between the symptoms that Irlen suggests to be associated with scotopic sensitivity syndrome and the symptoms associated with accommodative, binocular vision, and ocular motility disorders. Specifically, the following symptoms have been reported to be associated with both scotopic sensitivity syndrome or the Irlen syndrome41 and visual efficiency problems39,42,43: headaches, eyestrain, excessive blinking, excessive rubbing of the eyes, squinting, intermittent blur, occasional double vision, words appearing to be moving on the page, frequent loss of place, skipping lines, inability to sustain and concentrate, and rereading the same lines unintentionally. Could subjects diagnosed as having the Meares-Irlen syndrome simply have a refractive, accommodative, binocular vision, or eye movement disorder that has not been properly diagnosed?
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