Below is a review of the literature that refutes the common statements that dyslexia and vision are not related. Most of the bolding was added by me to bring out some points relevent to visual dyslexia.
Bowan MD. Learning disabilities, dyslexia, and vision: a subject
review. Optometry 2002;73:553-75.
I. Introduction
In 1998, the American Academy of Pediatrics, the American Academy of Ophthalmology, and the American Association of Pediatric Ophthalmology and Strabismus
(A A P / A AO/AAPOS) jointly published a position paper titled
“Learning Disabilities, Dyslexia And Vision: A Subject
Review.”1 This was an updated statement of their understanding of the role of vision in learning disabilities and
dyslexia (see Appendix). The new position paper followed
t wo comparable published papers—“The Eye and Learning
D i s a b i l i t i e s ”2 (1972) and “Learning Disabilities, Dyslexia And
V i s i o n ”3 (1981)—that drew the same conclusions: that visual
t h e r a py, lenses, prisms, and filters do not treat specific learning disabilities. [Author’s note: it should be noted that the
American Academy of Pediatrics was not a signator to the
1981 paper, but has rejoined to sign the 1998 paper.]
U n f o r t u n a t e l y, the 1972 and 1981 position papers suffered
from a lack of integrity in their scholarship. Each was studied and thoroughly discredited in papers published in a peer-reviewed journal4,5 for their corrupted use of references. Neither of these critical rev i ews was rebutted. The 1972 and 1981 position papers ignored the role of collateral visual and visual processing difficulties that the 1998 paper now a c k n ow l e d g e s. Howeve r, the authors of the 1998 paper have
failed to use this information in any constructive way for public and professional guidance. The literature review provided in this critical review and commentary refutes their unfounded charge that the literature fails to support a relationship between the visual process and learning.
Method: This article critically reviews and comments on the many
p roblems of scholarship, the inconsistencies, and the false
allegations the position paper presents. Perhaps the foremost
problem is that the authoring committee has ignored a veritable mountain of relevant literature that strongly argues against their assertion that vision does not relate to academic performance. It is for this reason that an overview, drawn from more than 1,400 identified re f e rences from Medline and other database sources and pertinent texts that were reviewed, is incorporated into this current article. The AAP/AAO/AAPOS paper is also examined for the Levels of Evidence that their references offer in support of their position.
Conclusion: The AAP/AAO/AAPOS paper contains errors and
i n t e rnal inconsistencies. Through highly selective re f e re n c e
choices, it misre p resents the great body of evidence from the
literature that supports a relationship between visual and perceptual problems as they contribute to classroom difficulties . The 1998 paper should be retracted because of the errors, bias,and disinformation it presents. The public assigns great trust to authorities for accurate, intellectually honest guidance, which is lacking in this AAP/AAO/AAPOS position paper.
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“The dissemination of this statement [the 1972
position paper]…does a disservice to the public and represents an affront to the academic community”; “…[the paper shows] gross distortion and inaccuracies in the use of the reference material”; “The distorted utilization of reference material is monumental”; “[The p a p e r ]…offers absolutely no supporting material for (its) conclusion”; and “This policy statement [the 1981 paper]…does the public a disservice… the references offered are misconstrued, non-applicable, and grossly distorted.”4.5
All of the references used negatively in the earlier position papers actually support a vision-learning link, according to the critics.
II. Examination of the 1998
AAP/AAO/AAPOS text
The 1998 AAP/AAO/AAPOS position paper (s e e
Appendix) appears to be essentially a rehash of
the earlier papers. However, in this new publication, there are only eight references from the 1990’s: two of which are policy statements on visual screening,Appendix refs. 8,9 one concerns a neurological basis for dyslex i a ,Appendix ref. 6 another is a poorly referenced opinion piece
with no data,Appendix ref. 24 and the other four are on Irlen lenses.Appendix refs. 18-20,23 One of the newer references (Solan, 1990) is used to support a negative position on “neurologic organizational training” [sic] when it addresses only Irlen lenses. In fact, the 1998 paper contains no actual research to support the allegation that there is no relationship between vision and
learning. The vast majority of the body of literature d o e s support a relationship; while it is relatively uncommon to find negative references, they d o ex i s t .
Starting with the Background statement, let us
examine the AAP/AAO/AAPOS position paper:
“Many educators, psychologists, and medical specialists concur that individuals who have learning disabilities should…avoid remedies involving eye exercises, filters, tinted lenses, or other optical devices
that have no known scientific proof of efficacy.” This statement is actually scientifically vague, lacking citations to support it. Because of the way it is worded, it implies that no eye exercises, filters, tinted lenses, and optical devices have any efficacy and that vision does not relate to learning,
Evaluation and Management
The authors make a statement that is inconsistent with the premise of the 1998 AAP/AAO/AAPOS paper: “Sometimes children also may have treatable visual difficulties along with their primary reading or
learning dysfunction.” It is important to point out that those treatable problems, in fact, may indeed require eye exercises, lenses, prisms, and filters, which were dismissed in the Background statement. This inconsistency escapes the authors. Their explanation goes on to state that visual acuity needs to be ruled in or out as a factor. However, this is generally a fruitless gesture in relation to reading retardation, since researchers and clinicians have long known that studies show an inverse relationship between visual acuity and academic performance. That is to say, reduced sight is often due to myopia, and myopia is frequently associated with above - average academic achievement and educational leve l .7 6 , 1 0 1 - 1 0 5 On the
other hand, low-to-moderate farsightedness rarely causes visual acuity problems, yet has been associated with visual perception and vision function anomalies. These children will pass vision screenings and yet may have academic difficulty.74,76,106-108
Role of the Eyes
The authors assert in an undocumented statement that: “some vision care practitioners incorrectly attribute reading difficulties to one or more subtle ocular or visual abnormalities.” Besides the lack of supporting citations from expert sources which might raise this statement to Level V ev i d e n c e, problems of definition arise. Who do the authors mean by “some vision care practitioners”? What do the authors mean by the nebulous term “subtle ocular or visual abnormalities”? Do they mean suppression? Suppression can be a co-existent visual abnormality in retarded readers, according to Benton (a pediatric ophthalmologist)1 0 9 and Safra.1 1 0
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Do they mean eye movement (saccadic) abnormalities? Deficient oculomotor abilities have been associated with reading disabled/dyslexic students.1 5 , 6 8 , 7 0 , 1 1 1 - 1 2 0 Do they mean accommodative difficulties? These, too, have been shown by researchers to be associated problems in some deficient readers.7 5 , 9 1 , 9 7 , 9 9 , 1 1 1 , 1 2 1 - 1 2 4 The omission of definitions and references is a significant difficulty.
The last sentence of this subtopic in the 1998
A A P / A AO/AAPOS paper states that children with
learning problems have the same ocular health as children without such conditions. Granted, ocular health has little (if any) relationship to learning. This non-issue appears to be introduced to impress the reader with a “piling-on effect” of negative statements. It is a moot point, however,
since there is very little basis for assertion that ocular health is related to learning problems.
The reason it is not used almost certainly has to be that the paper’s statistics omit the most salient of all data tests: the researchers completely leave out testing of the central question about the relationship between vision and learning and spuriously accept the null hypothesis. Nothing in the Helveston et al. paper supports the claim in their
abstract.126
Pa r a d ox i c a l l y, in the very midst of that potentially critical vision and learning study, and in an earlier paper based on a copying test of Helves ton' s creation (the “Draw a bicycle test”), the authors support educators’ and optometrists’ assertion that a strong relationship exists between visual-motor copying skills and academic performance.1 2 7 Helveston et al.’s data show a highly significant relationship between the two (p <
0.0001). It would appear that the unstated answer to their initial question of whether visual skills and learning are related is “Yes”.
Controversies
In this section the authors assert there is no scientific support for muscle exercises and “‘training’ glasses (with or without bifocals or prisms)”
i m p r oving academic abilities. The lack of appropriate scholarship is reflected here, since one of the three references used to support this statement refers only to Doman–Delecato cross-patterning training.Appendix ref. 15 Their statement is in direct contradiction to reports in the literature that support the observation that convergence insufficiency and suppression are associated with learning inefficiency and can be improved with orthoptic therapy and prism glasses.9 4 , 9 6 , 9 8 , 9 9 , 1 0 9 , 1 2 8 - 1 3 4 Most of these studies existed at the time of the publication of the 1998 AAP/AAO/AAPOS paper.
Perceptual therapy has been associated with improving academic abilities, in direct contradiction to the 1998 paper’s assertion that it has not. Rosner conducted several years of basic research in this area and found a high correlation of visual and auditory analytical skills to math and reading achievement. He developed a perceptual curriculum that remediated these skills and demonstrated a transfer of the improvement into academic performance.135-141 Most of this research was completed before the publication of the 1972 position paper.
Research supports at least some role of blue filters in assisting certain children with inefficient reading and attentional difficulties.1 4 2 - 1 4 4 However, the use of Irlen lenses (based on the Scotopic Sensitivity Syndrome) has never been a general optometric intervention, and is still a matter of great controversy. The American Optometric Association has appropriately taken a cautionary position in that respect.1 4 5 Even though the Scotopic Sensitivity Syndrome has yet to be demonstrated as a real phenomenon, the filter question is being examined, with at least some support for the validity of filters’ effect on the brain—probably in the magnocellular strata of the lateral geniculate nucleus. Ongoing research may lead to clinical guidelines for the use of filters as the relationships are clarified.
5 5 6
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The topic of expense of treatment is discussed, with the authors stating that the expense is unwarranted. This assumes that visual therapies or visual perceptual therapies are never effective. The very concept of this negative hypothesis is illogical. If parents pay tutors, psychologists, and educational specialists for assistance with their child’s learning problems, there will be less than effective results when there are visual barriers to learning that contribute in significant ways.9 6 , 9 9 , 1 0 3 , 1 0 8 , 1 0 9 , 1 1 7 , 1 3 0 - 1 3 2 , 1 3 4 Proper visual analysis and intervention need to be considered in all children with reading dysfunctions.
We often clinically see children with visual performance-related headaches subjected to extensive medical and neurological tests of great sophistication to reveal only normal results. A proper diagnostic protocol could potentially save parents and insurance companies great
amounts of unneeded expense. (Atzmon et al. found that, while both experimental groups improved in reading ability in their study, reading-disabled children who received visual therapy had a decrease in headache symptoms, but children who were only tutored actually had an
increase of headache symptoms. Their impression was that the tutored-only children were reading more, and this resulted in greater visual distress.128)
Further, taxpayers support special education programs that are populated by children with clinically significant visual function and visual processing problems.1 7 , 2 4 , 4 3 , 9 4 , 9 7 , 9 8 Learning support programs cannot effectively address children with the types of problems we are discussing here. The cost to society is additionally increased not only by these ineffectual attempts at rehabilitation, b u t — over time—by lost lifetime income,1 4 6 a greater incidence of crime in learning dysfunctional students (studies of juvenile delinquents and adult prisoners have shown that many are ‘retarded’ in reading1 4 6 - 1 5 0), and therapy for emotional sequellae.1 4 6 We would expect that any moneys productively spent in rehabilitating retarded readers by valid methods will potentially have great economic effect on any society.
Appropriate Educational Measures
The suggestion that “appropriate educational measures” be used in lieu of visual interventions is not as helpful as it might seem in the management of most of these cases. Children who are referred for visual and perceptual remediation (whether by psychologists, educators, or merely family friends) have often had years of public school and private tutoring for their problems. Clinical experience reveals that these children are often hardcore dysfunctional readers of many years’ standing, whose parents and schools have invested enormously in educational and medical interventions to little avail. They have been referred for visual evaluation only as a last resort, not as a first option. As an example of this, Solan et al. reported on therapies that were directed at
remediating 31 deficient readers with long-standing reading problems. These students had been addressed by traditional means for five
years, but at the end of the trial, had improved their learning rate (achievement divided by time on task) from a previous annual rate of 60% to 400% in 24 weeks—in spite of the many years of previous remedial interventions.151
Educational measures—intelligence, achievement, and related tests—fail to indicate what the teacher should do to assist children with learning skills problems: they merely reveal that a problem ex i s t s. Rosner demonstrated that if children have a visual-motor skills problem, they will
often have math, spelling (sight-words), and writing difficulties. Children with auditory-motor skills problems often will have reading, language
a r t s, and phonetic spelling difficulties.1 3 5 As mentioned prev i o u s l y, Rosner also proved that the perceptual skills deficiencies were remediable and transferred into classroom skills. “Teaching kids
harder” without addressing learning skills barriers is an inefficient use of the teacher’s time and resources when a child is experiencing visual-
motor or auditory-motor skills problems. This frequently will increase the chances that children with learning problems will develop anxieties and
depression over the learning experience,152-156 which further frustrates the child, the teacher, and the parents. Unfortunately, the most common
ways educators apply psychometric information is to adapt lessons, or to water down the content, or teach to the strengths. In a metastudy of this
last method, not one of the 15 papers that were considered provided a positive outcome.1 5 7 So, the AAP/AAO/AAPOS position paper’s recommendation to consult educators is less than useful, for all practical purposes. For pragmatic reasons, application of what is currently known from the body of neurobiological and neuropsychological research is not on the near horizon in the classrooms of America, unfortunately. Teachers are not yet trained as diagnosticians and clinicians, which presents a significant problem, since diagnostic skills are needed to address the differing learning styles and sensorimotor problems children bring into classrooms.64
At present, education has little to offer therapeutically to a student with perceptual and motor deficiencies, although individual teachers
may take the remediation of students’ specific problems upon themselves. The Bradley reference(Appendix ref. 21) has no data to support the assertion that the “reported benefits can be explained by
the traditional educational remedial techniques with which [training techniques and interventions] are usually combined.” This is one educator’s opinion . The Solan et al. study is primary evidence—of at least Level III quality—that nontraditional therapy can bring success to students when traditional educational remedial methods had failed (for five previous years).151
By inference, the 1998 AAP/AAO/AAPOS policy statement allows that even when physicians have no concrete suggestions, evaluation on a case-by case basis for visual processing problems is a waste of time. Proper visual analysis needs to be considered in all children with reading dysfunctions.
Early detection
This section raises a significant problem of definition. In the past, the word “dyslexia” referred to the inability to read due to known pathological or traumatic insult of the brain.77 (p. 2) That is no longer the case, as dyslexia has now become a layman’s catchword for “learning disability.”
The authors have separated the two concepts in the very title of the paper (“Learning Disabilities, Dyslexia, and Vision”), yet now blend the two into
one, and combine both with a third—Attention Deficit Disorder (ADD). Dyslexia, attention deficit disorder, and the most common learning
disabilities are three separate entities of symptoms with some crossover areas and need to be addressed as such. The authors seem to wish to
merge them in an apparent attempt to gain synergy for their efforts to ignore and discredit optometric therapeutic interventions. The literature
s h ows that ADD is only modestly related to academic difficulties.64 (pp. 151-192), 67, 158-160 However, Attention-Deficit Hyperactivity Disorder (ADHD) may have a vision connection in at least some cases: convergence insufficiency has been related to ADHD in one study.161
Role of the physician
The recommendations here are largely ineffective, since the direct instruction is for pediatricians to refer refractive errors, focusing deficiencies, eye muscle imbalance, and motor-fusion deficiencies
to ophthalmologists. At face value, this is not a bad recommendation, if we ignore the obvious inconsistency of this recommendation with their
Background Statement, because the problems mentioned generally require the use of lenses, prisms, and training they had recommended to
be avoided. However that may be, few pediatricians are in a position to detect these problems in a routine evaluation, and few parents will seek
out the pediatrician for a medical opinion when a child is referred from the school for a learning disability.162
It may be that the authors of the 1998
A A P / A AO/AAPOS paper intend something other than the most common understanding of “ocular defects” when they use that term. The authors, in this ‘Role of the Physician’ section, assure the reader there really are visual problems that need to be addressed. However, all vision care specialists will appreciate that focusing deficiencies, eye muscle imbalance, and motor-fusion deficiencies are not “ocular defects,” ipso facto. Therefore, the statement, “If no ocular defect is found, the child needs no further vision care or treatment…”—taken literally—is remiss, based on the findings of Helveston et al.,127 Atzmon et al.,128 Rosner,135-141 many others previously cited, and the very recommendations in the opening of the Role of the Physician’ section. The authors of this 1998 AAP/AAO/AAPOS text almost seem to wish to rush to close the door on any consideration of their admission that there are functional factors in the relationships of vision, visual processing, perception, and learning problems.
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In my opinion this article shows the reality that as far as vision and dyslexia go there have been many published papers that have opposing sides. In a careful reading of the literature I believe that the stronger position supports the idea that an optical intervention is possible. That the See Right Dyslexia Glasses offer that intervention I back with my guarantee.
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