A Discussion and Analysis, in the context of current research to May 2016, of:

A critical evaluation of the evidence supporting the practice of behavioural vision therapy Brendan T. Barrett (2009), Ophthal Physiol Opt 2009 29:4-25.

Authors: Leonard J Press OD FCOVD FAAO Mark Overton B.App.Sci, MBA Stephen Leslie B Optom FACBO FCOVD Ophthalmic Medicines Prescriber The Australasian College of Behavioural Optometrists June 2016

COPYRIGHT ACBO 2016 ALL RIGHTS RESERVED

Contents Introduction ...... 3

Convergence Problems ...... 6

Accommodation ...... 9

Strabismus & Amblyopia ...... 11

Yoked Prisms ...... 17

Low Plus Prescriptions ...... 21

Near-Point Stress and Low Plus Prescriptions...... 21

Plus near additions and Myopia ...... 25

Mainstream Optometry and Low Plus Lenses ...... 27

The Under-Achieving Child ...... 28

Dyslexia ...... 33

Dyspraxia ...... 34

Attention Deficit Disorder (ADD) & Attention Deficit Hyperactivity Disorder (ADHD) ..... 36

Sports Vision ...... 39

The Need for High Quality Research Studies ...... 42

A Brief Word About Evidence Based Practice ...... 43

Final Conclusion ...... 45

References ...... 46

2 | P a g e Introduction

The paper written by Brendan Barrett is often quoted by critics of behavioral optometry, but a close examination shows that the document:

1. Does not support the claim that there is no evidence basis for behavioral optometry

2. Is not indicative of current research and knowledge

3. Contains particular weaknesses that render it open to question.

A discussion document such as this cannot attempt to provide all of the evidence for behavioural optometry practices, or to point out all of the potential issues encountered when relying on an out-dated meta-study in a specialized field of knowledge. However, we will provide sufficient evidence to show that the paper written by Barrett in 2009, which has been used by some as a justification for a lack of “evidence based practice” for behavioural optometry, was and is incorrect in its conclusions, and has been largely invalidated by research in the eight years since. A clear and valid evidence base for behavioural optometry does exist, and Barrett’s paper is very open to interpretation when analysed in detail, and in fact is supportive of some aspects of behavioural optometry, even when written in 2009.

There is clear and unequivocal evidence for behavioural optometry practices, and as in any profession, clinical practice evolves and research evidence continues to mount. Sufficient evidence is provided here to make that point, and any assertions or claims that behavioural optometry lacks evidence do not stand up to scrutiny.

There are many papers written which relate directly and indirectly, to various practices in optometry which can broadly be categorised as “behavioural” optometry. In practice, the line between “mainstream” optometry and those optometrists who practice following the “behavioural” model of vision is more accurately represented by a continuum.

Birnbaum, one of the preeminent behavioral optometric practitioners of the past 50 years in the United States, noted that behavioral optometry has evolved along two complementary lines. Traditional, physiologically-based models emphasize accommodative-convergence

3 | P a g e relationships and the mechanisms of vergence dysfunction. Behavioral approaches emphasize the influence of environment and experience upon visual function, and the role of vision as a modality for gathering and processing information. He concludes, and this is crucial for the purposes of our discussion, that behavioral optometry is an integral part of optometric education and practice 1. The complementarity of physiologically-based models and behavioral approaches was recently elaborated by Doyle, an Australian behavioral optometrist 2.

Behavioural optometry concepts and practice have continued to evolve for over 90 years, with research increasingly providing strong evidence to support clinical experience and principles. For instance, research into development of myopia conclusively holds that myopia develops as a result of excessive near vision activity, combined with less time outside, with resultant changes in vision function and eventual axial growth. As such, there is rapidly growing research evidence to support the concepts and practice of behavioural optometry in management of myopia, as well as many other visual dysfunctions.

All optometrists must conform to Codes of Conduct, and practice standards that apply, and the commonalities between the models of practice far outnumber the differences. In Australia the great majority of practising optometrists are members of Optometry Australia, which has comprehensive Competency Standards3 to which all members are expected to practice.

Some of the relevant academic papers and writings evidenced in this document do not appear in the indexed ophthalmology, optometry, or orthoptics journals, but are no less relevant for that. It can mean however, that they can be missed.

In his introduction, Barrett sets the parameters for the nature and scope of his review deriving principally from the input of a behavioral optometrist appointed in an advisory role by the College of Optometrists to his commissioned project, and from his own review of the literature. As evidenced in our appraisal, the framework of behavioural optometry that Barrett presents as well as the sources cited is exceedingly narrow.

For example, at the time of Barrett’s review several optometric textbooks incorporating the behavioural model were available that lend more clarity to the discussion. These texts were

4 | P a g e not cited in the review and one can therefore presume not accessed. Since Barrett’s review represents Skeffington’s “4-circles model” as the cornerstone of the behavioral optometry approach, a more complete understanding of this model can and should be obtained from these sources. One is a textbook by Schmitt entirely devoted to the topic, and the other is a textbook by Press with one chapter devoted to the Evolution of Vision Therapy and another addressing Models of Vision and Their Therapeutic Implications 4 5.

In his 2009 paper, Barrett describes papers from 2006 as recent. There is a significant body of knowledge which has emerged since he wrote his paper. Older primary research can be valid for many years, and some academic papers are with us forever as classics. However, reviews such as Barrett’s are very time dependent and they can be outdated in months. Their content is interesting as a “snapshot” in that time, but users relying on them as mainstays of practice need to be sure that they continue to stay up to date with published new knowledge in specialized fields, else they risk their evidence base quickly becoming invalid.

On a number of occasions Barrett in his paper commences discussions with a statement implying a lack of evidence, and then goes on to refer to papers which actually do provide substance to the practices of behavioural optometry, undermining his own position. Using just the information in the paper itself, a detailed examination might easily lead to a conclusion that Barrett’s assertion, that there is a lack of evidence for behavioural optometry, looks to be overstated, if not simply invalid.

His only fair point seems to be that more research could be done, and that is always the case with any sub-set of science. To accept his discussion as proof that there is no evidence would only be made by someone who has either not fully read the document in detail, or who has not done their due diligence and read the references Barrett provides, or has chosen not to stay current with the field as it has developed over the last ten years.

We will now consider some of the specific subjects and points discussed by Barrett.

5 | P a g e Convergence Problems

Barrett states, “Recently, however, strong and persuasive evidence has emerged to support the efficacy of vision training (VT) in managing convergence insufficiency... it is now safe to conclude that this condition is amenable to treatment.”

Barrett goes to great lengths to point out that there have been critics of the evidence supporting treatment effectiveness. However, Barrett fails to provide the reader with the evidence needed to come to the same conclusion. For example, Barret suggests the work of Birnbaum et al (1999) was potentially influenced by the “Hawthorne Effect”. The criticism is fundamentally flawed and unfounded, as the Hawthorne Effect refers to human behaviour change under the influence of supervision, which regresses when the supervisor influence is removed. Birnbaum demonstrated measurable improvement in systems function which is a consequence of therapy, which is sustained. The patient’s vision has improved or it has not.

The paper by Barrett clearly shows support for VT as an effective treatment modality within behavioural optometry, and since his paper was published 10 years ago even more academic work has supported this area of practice. Some examples follow.

In 2008, presumably close to Barrett’s publication, Roy Beck and his co-authors 6 showed (in Archives of Ophthalmology) that twelve weeks of office based vergence/accommodative therapy with home reinforcement resulted in a significantly greater improvement in symptoms and clinical measures of near point of convergence and positive fusional vergence, and a greater percentage of patients reaching the predetermined criteria of success, compared with home-based pencil push-ups, home-based computer vergence/accommodative therapy and pencil push-ups, and office based placebo therapy.

Westmanna & Liinemaa (2012)7studied 135 patients and concluded that, “With orthoptic exercises it is possible to achieve longstanding relief of the symptoms of CI.”

Serna et al (2011, J AAPOS)8 were able to demonstrate that home-based computer based therapy reduced symptoms and improved near point convergence and fusional amplitudes; and that this is an effective option for treating symptomatic convergence insufficiency.

6 | P a g e McGregor (2014)9 states, “There is consensus among eye care professionals that convergence therapy is effective in treating convergence insufficiency.”

Sreenivasan and Bobier (2015)10 showed that the reduced vergence adaption and excessive convergence accommodation found in convergence insufficiency were normalized through treatment with vision therapy. These authors have produced a large volume11 of academic work in convergence and vision therapy.

Barrett states, regarding the Scheiman [CITT] et al study: “It is also hoped that the participants in the study will be subjected to long-term follow up in order to assess whether signs and symptoms of convergence insufficiency can be permanently resolved in an individual or whether repeated treatment are needed.” In fact, the CITT group did in fact demonstrate the long-term effective of treatment in this paper.

After acknowledging that available evidence suggests that accommodative disorders, CI and decompensating exophoria may respond to treatment, and that treatment effects are durable, Barrett notes that “the role of orthoptic exercises in the treatment of esophoria, however, remains unclear and needs further study”. Absent from Barrett’s review is research by Gallaway and Scheiman on the efficacy of vision therapy for convergence excess, which involved the treatment of esophoria. Their study resulted in the total elimination of symptoms in 80% of patients with convergence excess, and demonstrated that vision therapy alone is highly effective in eliminating abnormal vergence findings associated with esophoria at near 12.

The evidence is so strong now for the treatment of Convergence Insufficiency (CI) that follow on studies are beginning to look at the effects the CI directly has on issues which affect quality of life (QOL). In this vein, there is currently a very large program underway in the USA led by optometrist Professor Mitchell Scheiman to continue the work of the optometry and ophthalmology collaborative work of13 the Convergence Insufficiency Treatment Trial: Attention and Reading Trial (CITT-ART). This is a major randomized clinical trial evaluating the effect of vision therapy on reading and attention in school-age children with symptomatic CI, following on from the comprehensive CITT studies summarised by Scheiman et al in a Cochrane database publication14.

7 | P a g e It is noteworthy that contemporary research subsequent to Barrett’s paper supports the pervasive nature of vergence training not just on eye muscles, but in its salient effects throughout the visual pathways of the brain consistent with behavioural optometric theory. As an example, Alvarez and colleagues used fMRI to demonstrate enhanced functional activity within the frontal eye field, posterior parietal cortex, and cerebellar vermis as a result of vergence training 15.

Conclusion It appears that convergence therapy is supported by Barrett, and the examples we have presented show that VT is the most effective treatment for CI, now evidenced to a much higher degree by a large volume of research since Barrett’s publication.

8 | P a g e Accommodation

Barrett moves on from Convergence Insufficiency to say, “the treatment of accommodation disorders and other vergence disorders has not been subjected to the same level of attention in the recent scientific/clinical literature”. He then, to some extent, contradicts himself by citing a number of very significant articles on the subject of accommodation.

Barrett references seven papers authored by highly credible academics and clinicians - Weisz, (1979)16; Hoffman (1982)17; Aziz et al., (2006)18; Rouse, (1987)19; Grisham et al. (1991)20; Sterner et al. (1999)21; Ciuffreda, (2002)22; which demonstrate in Barrett’s own words, “accommodation disorders and a number of vergence disorders, in particular convergence insufficiency and decompensating exophoria may respond to treatment, and that, when they accrue, treatment effects are durable”.

In 2002 Kenneth Ciuffreda stated, “The findings (of the study) clearly support the validity of optometric vision therapy. Furthermore, the results are consistent with the tenets of general motor learning.”

Barrett then goes on to quote a further six 232425 important studies which, in Barrett’s own words, demonstrate that accommodative facility training is effective, and that, “these results, and the results from the many earlier studies of this nature are believable.”

Scheiman et al. (2011)26 also noted, “Vision therapy is effective in improving accommodative amplitude and accommodative facility in school-aged children with symptomatic CI and accommodative dysfunction.”

It is clear that at the time Barrett’s paper was written, Scheiman and many other prominent academics and clinicians supported the use of vision therapy in managing disorders of accommodation. This position has only grown stronger in the ensuing years, with publication of a large scale Randomized Clinical Trial by Scheiman et al. (2011) (representing the Convergence Insufficiency Treatment Trial Study Group) on accommodative dysfunction. This study conclusively demonstrated the efficacy of vision therapy, noting that: “Vision Therapy is effective in improving accommodative amplitude and accommodative facility in school-aged children with symptomatic CI and accommodative dysfunction." 27 9 | P a g e It is important to note that Barrett’s overall contention that an evidence base is lacking for behavioral optometry approaches completely bypasses the standard of care for these conditions by Optometry in the United States. These standards are readily available in the Clinical Practice Guidelines (CPG) published by the American Optometric Association. The most recent CPG on Accommodative and Vergence Dysfunction, with 196 references, was revised in 2010 and published in 2011. It concludes that the best treatment often involves a combination of lenses, prisms, and/or vision therapy, while noting that proper treatment usually results in rapid, cost-effective, and permanent improvement in visual skills 28.

Conclusion Research since 2008 has continued to develop an overwhelming body of evidence on the common incidence of accommodative dysfunctions in populations where prolonged near vision tasks are common, and that these dysfunctions are treatable with lenses, prisms and/or vision therapy.

10 | P a g e Strabismus & Amblyopia

Barrett makes a rather confident claim that, “Aside from such isolated case reports (which is a valid and commonly used form of clinical evidence) however, there appears to be a complete absence of evidence-based research to support claims that behavioural vision therapy is more effective than other forms of strabismus management, or that the behavioural approach is more effective than the no treatment alternative.” A statement like this could only be made by someone who shielded themselves from the body of literature available on the topic. There was, is, and continue to be valid academic papers and scientific studies supporting the behavioural optometry approach to treating both amblyopia and strabismus.

One wonders if Barrett’s knowledge of what constitutes the behavioural approach was sufficient for him to understand the field. Barrett relies heavily on the paper by Jennings as a way to sweep under the rug a major body of literature. He selectively has found some articles and uses these as representative of the whole. A recent literature search found 130+ articles on behavioural vision therapy for strabismus and another 240+ articles on behavioural vision therapy for amblyopia, all of which was already in the literature prior to Barrett writing his opinion piece.

The following are some examples from the literature. Wick (1987)29 wrote that a retrospective examination was performed on the records of 54 patients who had undergone vision therapy for accommodative esotropia. Over 90% of the patients achieved total restoration of normal binocular function with vision therapy, which would now be called behavioural vision therapy.

Zeigler, Huff and Rouse30 found sufficient published literature to perform a review of strabismus therapy in 1982, and although the reporting basis was not consistent in many, they showed cure rates based on Flom’s functional cure or equivalent of up to 73% from behavioural vision therapy.

Barrett notes that “many of the criticisms that are directed towards behavioural optometry concerning the lack of rigorous scientific evidence to support their approach, have also been

11 | P a g e levelled against the wider eye care community (both optometry and ophthalmology) which takes a more traditional approach to strabismus management”.

This speaks to the heart of Barrett’s apparent double standard of requiring more evidence for the behavioral approach than for other approaches. In fact, both references that he offers for Cochrane Database reports (on intermittent exotropia and infantile esotropia) have been updated (in 2013), and they still report the same conclusions concerning the lack of evidence for the efficacy of surgical interventions for strabismus.

A review of ophthalmology surgical and non-surgical interventions for intermittent exotropia conducted for the Cochrane Database (Hatt and Gnanaraj, 2006)31 concluded that the available medical literature consists mainly of retrospective case reviews which are difficult to reliably interpret and analyse. The one randomised trial included found unilateral surgery more effective than bilateral surgery for basic intermittent exotropia. However, across all identified studies, measures of severity and thus criteria for intervention are poorly validated, and there appear to be no reliable natural history data. There is therefore a pressing need for improved measures of severity, a better understanding of the natural history and carefully planned clinical trials of treatment to improve the evidence base for the management of this condition 32.

It should be noted in passing that standards for successful optometric treatment of strabismus typically relate to a functional result of binocular vision, whereas ophthalmological standards for strabismus surgery only aim for a cosmetic result, which can mean a remaining strabismus deviation within 10 prism dioptres of alignment, and no significant binocular vision function.

Also of note are the dramatically different criteria for success used by optometry and ophthalmology. As detailed above, ophthalmology seeks orthotropia after a surgery, the definition of which is that the eyes are now with plus or minus 10 prism diopters of being straight. Optometry has a much higher standard level of “functional cure”, looking to achieve the highest level of Flom’s criteria which includes binocular vision function and stereo acuity.

12 | P a g e A similar conclusion was reached in another Cochrane report by Elliott and Shafiq in 2005 concerning interventions for infantile esotropia (IE). “The main body of literature on interventions for IE are either retrospective studies or prospective cohort studies. It has not been possible through this review to resolve the controversies regarding type of surgery, non-surgical intervention and age of intervention. There is clearly a need for good quality trials to be conducted in these areas to improve the evidence base for the management of IE.”33.

Most of the discussion provided by Barrett around the use of therapy in the management of amblyopia is positive. He states, “...results are complemented by laboratory research studies showing that, with extensive practice, performance on positional tasks (which is particularly poor in amblyopes) can be improved substantially in children with amblyopia (Li et al.,2005). In addition to results in children, there are laboratory (Li and Levi, 2004) and clinical (Wick et al.,1992) studies suggesting that vision therapy and/or extensive task repetition in adults with amblyopia can also produce significant improvements in visual acuity, binocular function and positional acuity measures.”

He concludes on pp.14-15 of his review that the behavioural view runs contrary to a considerable volume of recent research evidence which indicates that refractive correction alone, or in combination with patching/penalisation is frequently associated with a high level of treatment success. However, this is very consistent with a behavioral view, as evidenced in the textbook Applied Concepts in Vision Therapy which states: “The judicious application of prescriptive lenses is always the initial step in amblyopia therapy”. The fact that this is frequently associated with a high level of treatment success with some patients does not obviate the need for additional intervention with other patients 34.

It would seem that Barrett’s literature search did not fully encompass the evidence available (a common issue).

Barrett quotes Wick & Wingard (1992), who concluded from a study of 19 patients that “following a sequential management plan for treatment of anisometropic amblyopia can yield substantial long-lasting improvement in visual acuity and binocular function for patients of any age. But there is plenty more evidence.”

13 | P a g e As early as 1978 Flax and Duckman35 reviewed several papers and showed orthoptic therapy produced a combined functional cure rate of 72.4% in patients with strabismus. NOTE: the “orthoptic therapy” as it was called then, is indeed nearly identical to that which the optometry field now calls behavioural vision therapy, except for the evolutionary changes which have improved the treatment.

In 1980, Goldrich studied the outcomes of 28 patients treated at the State University of New York, State College of Optometry and found that 71% attained a functional cure following sequential therapy procedures used in-office as well as home.

The 1999 paper of Krumholtz and Fitzgerald36 studied patients with refractive amblyopia and found that, although patching alone may be sufficient for improvement of visual acuity, binocular performance is significantly better when vision therapy is included in the treatment regimen.

Barrett does not quote the work of Cotter et al. in 199237 which showed a 59% success rate for vision therapy, which exceeded the success of surgery.

Since Barrett’s 2009 paper there have been a number of publications supporting the behavioural optometry approach. A review of Perceptual Learning (otherwise known as vision therapy) as a treatment for amblyopia by Levi et al (2009)38 showed that extant studies made it clear that practising a visual task resulted in a long-lasting improvement in performance in an amblyopic eye.

Alotaibi et al. (2012)39 demonstrated that patients with both moderate and severe amblyopia improved significantly when near therapy activities were included in treatment compared with the group without near therapy activities.

Gaishi et al. (2015) showed that deficits in motion-defined form perception were still present in 55% of patients at the end of patching treatment and identified the need for new approaches to amblyopia treatment.

A very significant development in amblyopia therapy evolved in mainstream optometric and ophthalmologic literature subsequent to the publication of Barrett’s paper that is predicated on behavioral optometric principles. This is the thrust toward treating amblyopia as a

14 | P a g e binocular vision problem treated primarily through binocular integrative therapy as opposed to occlusion/patching and/or penalisation. This approach has been championed by Hess in optometric circles in Canada, and supported by Wong and ophthalmologic colleagues in Canada based on newer understandings of brain processes in amblyopia and neuroplasticity. In a 2012 research paper on the subject, Hess and colleagues credit this approach in part to a paper published by Press in a journal that espouses a behavioural optometric approach 40 41.

There are now a growing number of publications demonstrating the usefulness of display technology including virtual reality in treating these conditions. Hess (2012)42 and subsequent follow up studies recorded positive results for therapy using iPad stereoscopic devices. Australian researchers have recently shown improvements in fine motor skills using IPod based therapy to improve binocular vision function in children with amblyopia 43

Barrett sets up a straw man argument that he could find no reports in the mainstream literature that have advocated, or even tested, “a purely behavioral approach to strabismus management (i.e. one that is based upon active vision therapy).” However, he again appears to have overlooked or ignored information from a Consensus Panel on Care of the Patient with Strabismus, published by the American Optometric Association. Originally published in 1995 and most recently reviewed in 2010, this Optometric Clinical Practice Guideline (CPG) on Care of the Patient with Strabismus includes 170 references supporting the role of vision therapy. One need not advance a “purely behavioral approach” to advocate for the application of behavioral principles in strabismus therapy. As this CPG demonstrates, surgical and non-surgical approaches can be synergistic in some cases 44.

In many cases, the specific treatment plan for an individual involves a number of modalities. However, most would agree that the conservative options should be applied first. From an optometric viewpoint this means that if a case can be cured with lenses alone then this is the best option. If it requires the addition of behavioural vision therapy this is the next best option. Some cases require surgery, but even in those cases, the patient benefits from some therapy being done before the surgery and therapy being done after the surgery. The debate about the proper sequencing and combinations of treatments for particular

15 | P a g e individuals imposes a responsibility on all clinicians to continue their efforts to find the best way forward.

Conclusion

We do not need to enter into the debate about which therapy or treatment option(s) are the ideal. Our purpose is to illustrate that there was, is, and continues to be valid and numerous academic papers and scientific studies supporting the behavioural optometry approach.

Optometric treatment of amblyopia and strabismus with lenses and patching, and in some cases vision therapy, is effective in many cases in achieving improved visual function to the high Flom criteria. Barrett’s criticisms are inaccurate and outdated. More research is needed to evaluate the individual benefits of all modes of delivery of treatment for amblyopia and strabismus, including optometric vision therapy and ophthalmological strabismus surgery.

16 | P a g e Yoked Prisms

Prisms are said to be yoked when both bases point in the same direction such as both bases up, both bases down, both bases right or both bases left. Since the earliest days of ophthalmic eyewear prisms have been incorporated in glasses primarily as a way to redirect the light into an eye that is turned relative to where it should be pointed in space to work with the other eye. This has helped many people who would have had double vision without this in their glasses.

The history of yoking the prisms is more recent but has a well-established history in the profession of optometry.

The first published references to yoked prisms use in vision training were by Horner 43 years ago in 197345, followed by Margach in 1981 46 47

Dr. Robert Kraskin published about the use of yoked prisms in 191-1983 as a series in Curriculum II of the Optometric Extension Program48. Soon after Dr Melvin Kaplan published his work entitled, “Vertical Yoked Prisms”49, in which he discussed his use of low powered prisms with populations of patients on the autism spectrum as well as patients with mild traumatic brain injury (TBI).

Barrett omitted other literature supportive of the application of yoked prisms in what he terms “neurologically normal patients”. The first is an extensive review of the subject by Press, which reconciles many of the apparent inconsistencies in the approach to prescribing which puzzled Barrett 50

In 1996, Harris published his paper, “The Behavioral Use of Prisms”51, which was part of a volume entitled, “Vision Therapy – Tools of Behavioral Vision Care: Prisms”, published by the Optometric Extension Program.

Barrett cites a lack of scientific study about the effects of yoked prism on posture, but omits two key research papers on the postural changes and perceptual shifts induced by yoked prism 52 53

17 | P a g e In 1998, Padula54 published his first theoretical construct for using yoked prisms in a population of patients with mTBI and in particular for helping to alleviate the postural difficulties which follow as a result of visual field disturbances, in particular right or left hemianopsias. All of these works were available to Barrett at the time of his writing.

Subsequently many papers have been published but of note is Harris’ chapter, “The Use of Lenses to Improve the Quality of Life Following Brain Injury”, which was published in the book, “Visual Rehabilitation – Multidisciplinary Care of the Patient Following Brain Injury”55 in 2011. And secondly, the landmark work by Padula et al, entitled, “Neuro-Visual Processing Rehabilitation: An Interdisciplinary Approach”56 also discussed in greater depth the use of yoked prisms for a multitude of conditions.

Vassilis Kokotas authored a masterful Ph.D. thesis (Aston University in the U.K.) on The Effects of Yoked Prisms on Body Posture and Egocentric Perception in a Normal Population. Using posturography and other scientific principles, his research demonstrated changes in body posture, mainly in the upper body and head, that are partially reflected in spatial perception tests and egocentric localisation directly attributable to the effects of yoked prism 57

Barrett (2009) notes that Lazarus, (1996)58, examined the effectiveness of yoked base-up prisms together with base-in prisms in alleviating asthenopia associated with computer use. The study employed a double-blind design in which spectacles which combined prism power with plus lens power were compared with those with plus lens power alone. Overall, there was a statistically significant preference for the spectacles containing the prisms

The rationale for use of yoked prism in vision therapy was provided by Fox 59. Begotka elaborated on the influence of yoked prism on spatial orientation 60.

Since 2002 there has been interest in the possibility that changes in visual input achieved through the use of yoked prisms can produce beneficial postural changes in adolescent patients with idiopathic scoliosis (Wong et al., 200261). Barrett (2009) suggests that more work needs to be done, however the results showed that yoked prisms could cause positive postural changes of significance.

18 | P a g e More recently, Howell has compiled a succinct review of the principles and applications of yoked prisms62.

A number of researchers have published papers on the effect of vertical and horizontal yoked prisms on normal posture. Huang and Ciuffreda found significant changes in egocentric localisation (sense of visual straight-ahead) and related body posture63. Michel et al found that horizontal yoked prisms caused significant changes in posture as a response to horizontal yoked prisms64.

Horizontal yoked prism can be applied in responsive cases of left visual neglect caused by right posterior parietal lesions, and Redding and Wallace reviewed the concepts and practice in 200665. Jacquin-Courtois described a case of a unilateral neglect patient who, with horizontal yoked prisms, showed better ability to drive a wheelchair66.

There are multiple published case studies of the application of yoked prisms in adults, and to date fewer publications of similar use of yoked prisms for children. However, yoked prisms are possible applications in comprehensive management of children with visual and postural problems associated with “…. attentional disorders, dyspraxia and fragile X syndrome” 67. Howell in his summary of yoked prisms applications, discusses a case of Williams syndrome where yoked prisms were considered by all the health care professionals involved to improve posture and visual-spatial-motor abilities.

Yoked prisms applied horizontally have also been suggested in cases of visual hemi-neglect, as well as to improve mobility in cases of Visual Midline Shift Syndrome, where the egocentric sense of visual straight - ahead shifts to one side, such that there is a mismatch of the visual sense of straight ahead with the facial and body midlines. Visual Midline Shift Syndrome not uncommonly occurs in people who suddenly lose vision of one eye, or experience a hemiplegia and/or hemianopic visual field loss as a result of a stroke or traumatic brain injury. This frequently results in the person having problems with balance, leaning/turning posture to one side, and even veering into the wall when trying to walk down a corridor68 69

19 | P a g e Yoked prisms and gait analysis have also been reported to have the potential to reduce the risk of falls and injuries 70 by restoring visual midline and improving balance, in some cases of traumatic brain injury, stroke and neurological disease.

Bansal, Han and Ciuffreda reported yoked prism prescription improved posture, balance and gait in two-thirds of 60 patients with acquired brain injury71.

Conclusion The clinical applications of yoked prism are rapidly evolving in areas as diverse as acquired brain injury, visual midline shift, postural dysfunctions, and treatment of adverse esophoria. While the theoretical basis of effects of yoked prisms on visual spatial judgement is reasonably well understood, both the theory and practice of application of yoked prisms would benefit from further well-designed research.

20 | P a g e Low Plus Prescriptions

NEAR-POINT STRESS AND LOW PLUS PRESCRIPTIONS

Behavioural optometrists use low plus prescriptions to optimise near vision performance, based on well-established clinical regimes of assessment of refraction, accommodation function, distance and near phorias, and vergence function, in relation to the symptoms and visual performance issues of individual patient concerns.

This is based on the behavioural concept that refractive deviations from the norm of minimal hyperopia, such as myopia; and binocular vision dysfunctions, such as esophoria and high exophoria; develop as a result of gradual adaptations over time of the complex visual system to frequent and sustained episodes of near visual demand, such as reading, computer and I-device use. This can cause fatigue of accommodative and vergence accuracy, with near vision-related signs and symptoms, effects on visual performance, and gradual adaptation to the physiologically adverse task demand, or task avoidance in some cases.

This concept is different to the traditional optometric and ophthalmological concept that refractive errors and binocular vision dysfunctions just happen for no reason, a surprisingly unscientific concept which is rapidly being eroded as a result of research into development of the worldwide epidemic of myopia.

Barrett’s contention in this section rests primarily on two points:

1. “Low-plus prescriptions are advocated before anything appears to be abnormal on evaluation using a traditional optometric approach”.

2. “The ‘low-plus for relief of near point stress’ is therefore a controversial approach because in many instances it suggests that refractive correction should be worn even when the patient is wholly asymptomatic.”

Regarding the first point, the fact that case analysis in a behavioural approach may point toward a low-plus prescription for select patients in the absence of abnormalities detected

21 | P a g e using a traditional optometric approach, may reflect a limitation in the traditional approach rather than a problem with the behavioural approach. Once again, Barrett appears to have overlooked or ignored evidence supportive of the behavioural approach in this section. The most obvious source in this regard is the classic textbook on the behavioural approach to vision dysfunction by Forrest, documenting and supporting the rationale for an expanded view beyond traditional approaches 72.

In their textbook on Clinical Pearls in Refractive Care, used as a primer for their course at the State University of New York’s College of Optometry, Werner and Press point out the limitations of traditional optometric case analysis for a wide variety of conditions, and the importance of considering a behavioural approach 73.

Barrett’s second point, that a lens prescription should only be prescribed when a patient is symptomatic, merely reflects a limited view of visual dysfunctions and the impact of lenses on performance 74.

Behavioural optometrists commonly employ, as do other optometrists and some ophthalmologists, near retinoscopy to objectively measure the accuracy, equality, stability or fatigue, and response to lenses, of the accommodative system.

Different powered lenses can be trialled with near (sometimes called dynamic) retinoscopy to aid in determining the best prescription for reading, computer use and iPad and iPhone use, as distinct from the limited distance refraction traditionally employed by many. The technique is used by many optometrists who work with children and adults with near vision symptoms.

Dr David Lee Guyton, Professor of Pediatric Ophthalmology, John Hopkins University School of Medicine states “The technique (of near retinoscopy) has been extensively investigated by the optometric profession…... It can be of value in screening infants for astigmatism and anisometropia, in detecting incomplete cycloplegia (paralysis of focus), in detecting abnormalities of accommodation (focusing ability), and probably in determining the treatment strategy for eyes with amblyopia (lazy eye) and deficient accommodation.” 75

22 | P a g e Boston Children’s Hospital Professor of Ophthalmology Dr David Hunter writes “This clinical tool can provide critical data that can help solve treatment dilemmas, such as when a child presents with high hyperopia (long sightedness) or when a patient presents at any age with possible accommodative insufficiency (focusing inaccuracy).” 76

There are indications that uncompensated hyperopia can interfere with the reading and learning process, and therefore plus lens application may be considered even in the absence of symptoms – particularly among children who are receiving special education services. Research from Quaid and Simpson in Canada looked at the nature of hyperopia in students with IEPs (Individualized Education Plans in Special Education Servies) as compared to controls. The IEP group had significantly greater hyperopia relative to the control group on cycloplegic examination. Furthermore, vergence facility was significantly correlated to (i) reading speed, (ii) number of eye movements made when reading, and (iii) a standardized symptom scoring system. Vergence facility was also significantly reduced in the IEP group versus controls. Significant differences in several other binocular vision related scores were also found 77.

There are a number of important papers that Barrett missed. Larabee and Jones (1980)78 looked at the relationship between the application of low plus reading lenses and the improvement of performance at a child's near working distance. Statistically significant behavioural changes were associated with wearing the low plus-power reading lenses while performing the near paper-and-pencil task.

Greenspan (1990)79 demonstrated clinically significant improvement in overall visual efficiency using low plus lenses relative to the subject’s ametropia correction. In other words, if a person needed glasses for correction of a refractive condition such as myopia or astigmatism, they had improved visual efficiency on near tasks if a low plus lens power was added to their correction. The data for all subjects suggested trends related to the relative lens power, and in this case the lens powers were low plus. These trends featured systematic alterations in near point working distance and performance with reference to a critical low powered plus lens approximated by dynamic retinoscopy for each subject80.

23 | P a g e Subsequently, Iyer and Harris (2013)81 demonstrated that low plus lenses had a significant positive effect on reading comprehension as well as improving reading speed for all subjects (p<0.001). Objective data for this study was obtained using infrared eye movement recording devices, and the “N” for the study was large enough for these finding to be quite clinically significant.

Barrett notes that the debate around this area of treatment is widespread. He says, “However, it should be pointed out that controversy associated with the issuing of low-plus corrections in pre-presbyopic individuals, particularly in children, also extends to traditional optometric practice.” So it appears Barrett is unable to level a specific criticism at behavioural optometry in this area as compared to optometry and ophthalmology.

Conclusion

Work in the area of the use of low plus prescriptions for accommodative-convergence dysfunctions continues, with well - established textbooks and a plethora of papers showing strong evidence for models of accommodative convergence dysfunction, and application of low plus lenses where indicated by competent clinical assessment. It is clearly not reasonable to criticise behavioural optometry on this basis.

24 | P a g e PLUS NEAR ADDITIONS AND MYOPIA

In his 2009 paper Barrett notes, “There are a number of aspects of the behavioural approach to explaining the origins of myopia with which the research and traditional optometric communities might agree.”

Barrett extensively quotes from the work of A.M. Skeffington. However, at one point he attempts to paraphrase Skeffington by saying that Skeffington says that, “over convergence is a causal agent for myopia”. This shows a fundamental lack of understanding of Skeffington’s writings and intent. What Skeffington said, and which was quoted accurately on page 8 of Barrett’s paper was, “the near work demands imposed by our culture are incompatible with our physiology and provoke a stress response characterised by a drive for convergence to localize closer than accommodation”. Thus, Skeffington never said that the over - convergence was a causal agent. He said that as a person works to meet the demands of our culture, the physiological stress response triggers or manifests as convergence being postured closer in space than to the location to where accommodation is responding. This results in the measurement of esophoria at near when the person is under prolonged near vision demand. This same observation is supported by evidence from Goss (1991)82. However, one must be clear that the measurement of the “esophoria at near” by no means suggests that the esophoria itself is the causative agent of progressive myopia, rather it is a result of a pattern of accommodative and vergence dysfunction.

Evidence suggests (Gwiazda et al., 2003)83 that substantial reading additions (e.g. +2.00 D) provided too pre-presbyopic patients can slow the progression of myopia by a statistically significant amount.

Barrett (2009) notes, “In relation to the behavioural optometry prediction that esophoria will be present in individuals with progressing myopia, ...... there is now a good deal of evidence showing that more slowing of myopia progression occurs in patients with esophoria at near (Goss,199184; Fulk et al.85 , 2000; Brown et al., 2002).” In these studies, low plus lenses at near were prescribed to just eliminate the esophoria, based on the principles of behavioural optometry.

25 | P a g e Regarding the effect of plus lenses at near and the progression of myopia, Goss and Rainey provide evidence of the impact of plus lenses, particularly when there is esophoria at near. They note, and this is a crucial point, that a limitation of much research on the effect of a plus lens addition on myopia progression, is that an arbitrary plus lens value or addition at near is used for all subjects rather than individualizing these powers based on their plus lens acceptance profile 86.

A study of over 5,000 eyes by Huang et al (2016)87 showed that a range of interventions can significantly reduce myopia progression when compared with single vision spectacle lenses or placebo. In terms of refraction, atropine, pirenzepine, bifocal soft contact lenses and progressive addition spectacle lenses were all found to be effective in slowing myopic progression. Pharmaceutical intervention was most effective, but the secondary side effects on accommodation later in life, and other problems have led to limited application of some of these approaches, although the use of low dose atropine is gradually building a clinical and research support.

Gifford has recently published a comprehensive review of contact lens management of myopia, in advance of her PhD completion, on current understanding of theoretical and clinical aspects of myopia, in which she states “standard single vision spectacles, rigid contact lenses and soft contact lenses do not offer any useful myopia control effect” 88.

Conclusion This subject is now an area of interest to the broad optometry and ophthalmology communities, and certainly is not confined to behavioural optometry, and Barrett’s criticisms of behavioural optometry are no longer valid, and in fact critical of mainstream accepted best practice for management of myopia.

26 | P a g e MAINSTREAM OPTOMETRY AND LOW PLUS LENSES

In his 2009 paper, Barrett notes that the controversy associated with the issuing of low-plus corrections in pre -presbyopic individuals, particularly in children, also extends to traditional optometric practice (e.g. Donahue, 200489; Robaei et al., 200690; Ip et al, 200691; Filips, 200892). For example, in a recent, large-scale study of over 2300 12-year-old Australian children, Robaei et al. (2006) concluded by saying that the recommendation by the American Optometric Association for the use of plus lenses for the treatment of convergence excess, accommodative insufficiency, or in-facility, ill-sustained accommodation, or spasm of accommodation, is a practice that is well reflected in their study population in Australia.

It should be noted that Filips firmly refuted the Robaei articles, citing several major important flaws in the study, most of which simply reflect worldwide philosophical differences between the approaches of ophthalmology and optometry at large. As noted, the American Optometric Association represents all optometrists in the United States and their Clinical Practice Guidelines clearly indicate that low plus lenses are recommended for a number of conditions, and that this is not a disparate behavioural optometric stance.

27 | P a g e The Under-Achieving Child

Barrett begins with the premise that parents of children with the conditions he identifies are somehow “vulnerable”, as he puts it, with the implication that they are being taken advantage of by predatory behavioural optometrists wielding treatments without evidence. This is an ophthalmologic point of view as expressed in position papers 93, which has been thoroughly refuted by Bowen’s review paper 94, which Barrett cites, and also with an updated rebuttal by Lack 95 published after Barrett’s 2009 paper, showing that this framing bias continues. There is simply no factual basis for the implications or accusations that, in Barrett’s terminology “disillusioned parents are having expectations falsely raised”

In short, behavioural Optometrists do not treat dyslexia in children and adults. This is clearly stated in policies and publications of Optometry Australia, the Australasian College of Behavioural Optometrists, the American Academy of Optometry, and the American Optometric Association. Psychologists test for and diagnose dyslexia.

However, a behavioural optometrist will test, diagnose and manage any visual dysfunction that may also co-exist with the diagnosis of dyslexia, which may interfere with the process of reading and writing, as well as limiting the potential benefits of other therapies for the dyslexia.

A full assessment performed by behavioural optometrists may identify vision problems which can affect reading speed, fluency, concentration and comprehension. By identifying and treating the visual problem, often reading speed and comprehension improve without direct reading instruction. However, the primary concern of all optometrists are their patient’s visual problems. Optometrists only treat the concurrent visual problems which affect reading and are not treating the dyslexia. This is a common misconception amongst critics of behavioural optometry. It may be that on occasions the results of an optometric examination are suggestive of dyslexia, and the optometrist would make an appropriate referral for further assessment.

Consistent with the behavioural optometry approach to this population, the American Academy of Optometry issued a comprehensive review in 2013. The position paper reviews

28 | P a g e recent studies providing new insights into accommodative and vergence disorders that reinforce the need for comprehensive eye examinations and follow-up care for students who are struggling in school. It notes that the typical student with an accommodative or binocular disorder will often experience fatigue, loss of place when reading, decreasing comprehension over time, and difficulty completing assignments. These difficulties may not fit exclusively into the currently accepted categories of problems that adversely impact a student’s school performance such as a specific learning disability, attention deficit hyperactivity disorder (ADHD), or language-based dyslexia. The position paper concludes that timely identification and treatment of eye focusing and teaming problems can remove a potential obstacle that may restrict a child from performing at his or her full potential 96.

It is widely acknowledged that causes of underachievement are multifactorial. Therefore, the thrust of Barrett’s argument that vision problems don’t cause underachievement in isolation is irrelevant, as long as it can be demonstrated that vision problems may interfere significantly with the ability to learn.

Evidence for this is amply provided in another Clinical Practice Guideline from the American Optometric Association on Care of the Patient with Learning Related Vision Problems. This compilation of 205 references concludes that vision problems, comprising deficits in visual efficiency and visual information processing, have a relatively high prevalence in the population, and can interfere with the ability to learn. These deficits may cause clinical signs and symptoms that range from asthenopia and blurred vision to delayed learning of the alphabet, difficulty with reading and spelling, and skipping words and losing place when reading. They respond favorably to the appropriate use of lenses, prisms, and vision therapy, either alone or in combination 97.

Regarding specific conditions associated with under-achievement, such as ADHD, Barrett contends that there is a lack of evidence that visual difficulties contribute to these disorders. In their journal article offered for continuing education credit by the California Optometric Association, Hong and Press identify the role of visual factors in various childhood behavioral disorders. Included in this is a rationale for the impact of vision disorders on ADHD 98.

29 | P a g e Even when accommodation and vergence are normal, eye movement abnormalities can occur with dyslexic children which contribute to their reading difficulties. In studying this relationship, Tiadi and colleagues published credible evidence that dyslexic children exhibit many more difficulties of control of saccades during fixation than age-matched non-dyslexic children. They concluded that orthoptic as well as visuo-attentional training in dyslexic children could help them to better focus their attention and therefore decrease reading errors and/or word omission 99.

According to Barrett (2009), “Although few would argue that vision problems can interfere with reading/learning, what it is not well established is the extent to which visual problems represent an underlying cause of the dyslexia.” Behavioural optometry has never taken the stance that vision is an underlying cause of dyslexia, but it is common clinical experience, and there is now strong published evidence, that children in this group have a higher incidence of visual dysfunction than the general population, once again highlighting the dangers of relying on outdated meta-studies.

The role of abnormalities in visual attention and its influence on reading has mushroomed since the publication of Barrett’s paper. Countering Barrett’s contention that it is correlation but not causation when it comes to visual factors in dyslexia, Facoetti’s laboratory in Italy has established a causal link between visual spatial attention and reading acquisition. They conclude: “Independent of speech-sound perception, as well as non- alphabetic cross-modal mapping skills, visual attentional functioning predicts future reading emergence and development disorders. These findings virtually close not only a long-lasting debate on the causal role of visual spatial attention deficits in dyslexia but also open the way to a new approach for early identification and more efficient prevention of dyslexia 100.

In fact, much of the evidence published since Barrett’s paper points toward vision playing a more prominent role in dyslexia. A particularly compelling paper by Vidayasagar and Pammer argues that attentional mechanisms controlled by the dorsal visual stream help in serial scanning of letters, and that any deficits in this process will cause a cascade of effects, including impairments in visual processing of graphemes, their translation into phonemes and the development of phonemic awareness. This view of dyslexia localizes the core deficit

30 | P a g e within the visual system and supports the role of optometry in early detection and intervention 101.

Research continues to point toward untreated visual abnormalities as a risk factor in the development of dyslexia. A study by Ortiz and colleagues in Spain compared children from preschool with and without risk for dyslexia in auditory and visual temporal order judgment tasks. Results revealed that the visual as well as the auditory perception of children at risk for dyslexia is impaired. The difficulties of children at risk in visual and auditory perceptive processing affected both linguistic and nonlinguistic stimuli. They concluded that these visual and auditory perceptual deficits reflect a basic temporal processing deficit contributing to the failure to learn to read, rather than being the consequence of reading difficulties 102.

Creavin et al (2015)103 studied 172 children with severe reading impediment (SRI) and found that 2 in 10 children with dyslexia have proven vision problems. Abnormalities in sensory fusion at near were higher in children with SRI compared with their peers (1 in 6 vs 1 in 10), as were children with stereo acuity worse than 60 seconds of arc (1 in 6 vs 1 in 10). There may not be a direct association between dyslexia and vision problems, but children with dyslexia have at least the same if not greater incidence of vision dysfunction than the general population. In fact, the Creavin study demonstrates that dyslexic children have vision problems that occur 50% more frequently than in the general population.

In the UK, where the Creavin paper population was based, there are 375,000 children with dyslexia and 60,000 with dyslexia have associated vision problems, according to the study. With these rates of concurrent visual dysfunction, it would logically follow that a visual assessment should be part of assisting a child who has indications of, or has been diagnosed with dyslexia.

To quote Evan Brown, in a study in process, “Clinically, primary care optometrists are frequently consulted by parents and teachers of children and teenagers underperforming in literacy achievement, looking to eliminate vision as a contributing factor. Standard primary care assessment limited to visual acuity, ocular health and refractive error are unlikely to uncover a visual dysfunction related to learning as these ocular conditions only have weak correlations to academic performance 104 105.”

31 | P a g e When considering refractive error, hyperopia has been shown to have the strongest association with decreased reading performance106 107 108.

To adequately answer the question of whether a vision problem exists, that may be contributing to a learning difficulty, the literature suggests best practice involves a full survey should be conducted of visual efficiency skills, also known as functional vision skills (oculomotor function, binocular and accommodative function) and visual information processing skills (visual perception abilities and visual-motor integration abilities)”. Optometric treatment of functional visual skills dysfunction has a very strong evidence basis, as summarised by Ciuffreda109 .

32 | P a g e Dyslexia

There are glaring omissions in Barrett’s review of vision and dyslexia. For example, the extensive clinical research by Griffin and colleagues on the nature of visual dysfunctions in reading and proven interventions is well summarized in his 1996 textbook on the subject 110.

There is a lack of reference to the work of Dr. Harold Solan, one of the most prolific researchers in optometry who has modeled the influences of visual factors in reading performance and effective interventions through vision therapy. Solan’s research was summarized in an authoritative textbook on Models of the Visual System edited by Hung and Ciuffreda, as part of Springer’s series on Topics in Biomdedical Engineering 111. Solan reviewed the clinical implications of optometric research regarding visual perceptual factors in reading, a body of evidence glossed over by Barrett 112.

Solan and colleagues showed the role of vision therapy in improving reading performance in a paper published in the Journal of Learning Disabilities. Eye movement therapy improved eye movements and also resulted in significant gains in reading comprehension. The results support the link between visual attention, oculomotor readiness, and reading comprehension 113.

Conclusion Behavioural optometrists do not treat dyslexia. They test and treat visual dysfunctions which interfere with a child or adult’s ability to use vision to read or write, and which can adversely affect reading comfort, speed, accuracy, concentration and comprehension. The incidence of visual dysfunctions in children with dyslexia or reading problems is much higher than in children with no reading issues, and these problems should be detected and treated to minimise or eliminate visual impediments to a child’s ability to access the curriculum, and to benefit from other reading interventions.

33 | P a g e Dyspraxia

Barrett dedicates a section under the umbrella of the under-achieving child to Dyspraxia, also known as Developmental Coordination Disorder (DCD), as a diagnostic entity for which there is little evidence that vision or vision therapy plays a role. However, a recent study by Rafique and Northway in Canada runs counter to his conclusions. They assessed visual function, gross and fine motor skills in children with developmental coordination disorder (DCD) as compared to typically developing control children. Children with DCD had significantly poorer accommodation facility and amplitude dynamics compared to controls. They concluded that anomalies of accommodation contributed to the ineffective coordination of action and perception seen in children with DCD114 .

Barrett discusses the nature of Dyspraxia or Developmental Coordination Disorder (DCD) at some length and also mentions research into the relationship between DCD and perception. At the time of writing his paper it seems that there was quite some way to go in understanding DCD. He does not provide any evidence that Behavioural Optometrists claim to cure or treat either Dyspraxia or DCD.

Like Dyslexia, optometrists do not claim to be able to cure DCD, but they do treat associated visual dysfunctions which may occur concurrently in the patient with DCD. However, there is now emerging evidence that vision is important in this syndrome.

This important point is acknowledged by Barrett (2009), “In a very recent study, Crawford and Dewey (2008)115 found that the number of co-occurring disorders present with DCD (e.g. reading/learning difficulties, attention deficit hyperactivity disorder) is associated with the severity of the visual perceptual dysfunction.”

Barrett correctly makes reference to a case study by Hurst (2006)116, which shows a significant improvement in an 8-year-old boy with DCD. Hurst acknowledges that there is more study required.

Since then (again highlighting the dangers of relying on an outdated meta-study), a study of 32 children by Coetzee (2013)117 has demonstrated that visual therapy contributed to a

34 | P a g e significant improvement of 75% to 100% in visual pursuit, fixation, ocular alignment and convergence, with significant lasting effects (p<0.001).

Other research has shown that the visual system is significantly involved with DCD. Robert (2014)118 concluded, “...results (of the study) suggest a delay in the maturation of the pursuit system in children with DCD.”

It seems that some ophthalmologists also agree. Arents et al (2012)119 suggest in the Journal Français D'Ophtalmologie that, “... consultation is an essential step in the diagnosis and treatment of learning disorders, particularly in children with dyspraxia. Such a specialized consultation allows identification of cognitive visual disorders, especially oculomotor or visual-spatial impairment, which disrupt the cognitive processes involved in key academic tasks such as reading or handwriting.”

Barrett spends considerable time quoting various references and authorities to demonstrate that behavioural optometry and vision therapy have no evidence for the treatment of “complex paediatric developmental and neurologic conditions”. His purpose in labouring this point remains unclear, as Barrett acknowledges, and we concur that vision therapy does not directly treat these conditions, rather optometric treatment improves the visual issues which co-exist and/or contribute to the visual spatial motor performance concerns.

Conclusion There is strong current evidence to suggest that vision dysfunction occurs perhaps with greater frequency and concurrently with syndromes like dyslexia and dyspraxia, and that the vision dysfunction can be treated and managed.

Barrett’s criticisms of behavioural optometric care of children with dyspraxia are based on a false premise, and contradicted by some of his citations, as well as by subsequent published studies.

35 | P a g e Attention Deficit Disorder (ADD) & Attention Deficit Hyperactivity Disorder (ADHD)

Once again Barrett starts his discussion with an unsubstantiated statement - “It is claimed that behavioural vision therapy can be beneficial in children with ADHD and ADD”. By now it would seem obvious that if an accusation of “lack of evidence” is to be levelled at optometrists making a claim to treat a concern, it is best to offer evidence of this assertion. To make this a legitimate concern for users of this paper as evidence in and of itself, proof would need to be provided that more than a few behavioural optometrists make this claim.

As is the case with dyslexia and dyspraxia, behavioural optometrists do not diagnose ADD or ADHD, but are aware that a higher proportion of children with ADD and ADHD concurrently have an incidence of visual dysfunctions, than the incidence in the general population

Once again Barrett states there is little evidence, and then notes several papers that do provide evidence. For example, Granet et al. (2005)120 have reported that the prevalence of convergence insufficiency in the ADHD population may be three times higher than in the population at large. He qualifies the conclusions of the Granet paper as follows, “However, Granet et al. acknowledge that this may simply represent an association rather than a causative relationship.” This would only be a relevant statement if an optometrist was claiming to treat ADD or ADHD. A later study by Gomes and Barbosa (2014)121 published in Archives of Disease in Childhood supports the theory that there is a high prevalence of convergence insufficiency associated with ADHD.

It has been established, and Barrett has conceded on the point that there is clear evidence for the effectiveness for the treatment of concurrent convergence insufficiency with vision therapy, yet Barrett continues to make unsubstantiated and prejudicial statements.

For example, “But what is the evidence that optometrists adopting a behavioural approach can offer therapy that will positively influence the lives of children with these signs or formally diagnosed conditions? Demonstrating treatment efficacy is especially important here because these children and their parents represent a vulnerable group)..., the onus is clearly on treatment providers to produce the evidence in support of the treatment(s) that 36 | P a g e they are offering. Without such evidence, parents inevitably run the risk of wasting their time, effort and resources, and they and their children may become disillusioned if expectations are repeatedly raised and then dashed.”

Recent studies assessing attention related vergence in children with ADHD support the observation of deficient binocular vision in ADHD patients 122.

Once again Barrett looks at the situation from the perspective that optometrists are treating the primary disorder, when he acknowledges that optometrists treat the concurrent vision problems. These vision problems are proven to exist in higher incidences in patients with conditions such as ADHD, DCD and dyslexia; and we also know that evidence demonstrates optometric treatments are effective for the vision disorders.

Having made the above statement, he belatedly writes “It is worth pointing out that behavioural optometrists believe that vision therapy can be beneficial in these conditions, not because the condition is being cured, but because it enables the child to operate more efficiently in spite of the condition.” The casual or uncharitable reader might easily overlook such caveats. This seems to be a common approach in his discussion around, “The Underachieving Child”.

Barrett also claims that a causal relationship between the primary disorder and concurrent vision problems is required. A causal relationship is not the issue, rather a child with ADHD may also have a visual dysfunction which could be treated and managed. A child with ADHD will most likely be hindered even more by also having a less than optimally performing visual system. Therefore, it is quite reasonable (provided there is no claim to treat the primary condition) for optometrists to suggest that they can improve visual function in children with these conditions. Barrett agrees that they can achieve improvements.

Lee et al (2014)123 established that, “convergence insufficiency symptoms are closely related to symptoms screened for ADHD, and vision therapy to improve vergence movements is an effective method of decreasing the Korea-ADHD Rating Scale scores.” They found that near positive fusional vergence and near exophoria significantly improved compared to their values before vision therapy.

37 | P a g e Conclusion

Even despite Barrett’s inconsistent approach, there is a body of evidence that behavioural optometrists’ may reasonably call upon to support treatment of visual dysfunctions in children diagnosed with attentional disorders.

Behavioural optometrists do not specifically treat ADD or ADHD, they treat visual dysfunctions which occur in people with attentional issues (who have a higher incidence of vision problems than in the general population). Barrett’s statements in this area are contradictory, and there is significant subsequent evidence of the co-existence of visual dysfunctions in the ADD/ADHD population, and that these visual dysfunctions are treatable.

38 | P a g e Sports Vision

Barrett shares with many people a common misunderstanding of sports vision care. At a primary care level, optometric sports vision involves comprehensive assessment of a sports participant’s vision function and ocular health, in relation to their visual activities in everyday life, at work or in study, and involvement in sport. In relation to sport, the visual demands of the particular sport are analysed, and firstly prescriptive aids (spectacles and contact lenses) are prescribed to ideally meet the sport’s visual demands, for example in shooting, archery and snooker.

As well, it is incumbent on an optometrist to provide eye protection where indicated, for participation in sports which are eye safety hazardous, particularly squash, cricket and indoor cricket, hockey and basketball.

At the next level, an optometrist can detect visual dysfunctions which potentially can interfere with a person’s ability to use their vision to perform in sport to their potential. This may include deficiencies in binocular vison, such as high exophoria or esophoria, and even subtle or overt strabismus, which can interfere with spatial localisation of a target or ball, decrease depth perception, and cause delays in changing accommodation-vergence from near to far to near, as in tennis, squash, cricket and baseball. These visual dysfunctions can be treated, as detailed above, to remove visual dysfunctional impediments to using vision optimally for sports performance.

At another level, a small number of practitioners (non-behavioural and behavioural) in Australia and overseas provide assessment of visual-spatial- motor abilities, (including visual reaction times, eye hand coordination and speed, depth perception and tracking eye movements), which can potentially impact on sports performance and an athlete’s potential at an elite level. Deficient visual abilities which are correlated by the optometrist, player and coach may be improved using vision therapy.

Kundson and Kluka review how visual abilities affect sport performance and the acquisition of motor skills, and can be improved with training. They summarize important vision

39 | P a g e information related to performance in sport and show how vision training improves performance 124.

In Germany, Schwab and Memmert conducted research demonstrating that certain visual abilities of youth field hockey players, such as the peripheral perception or the choice reaction time are trainable and can be improved by means of an appropriate visual training 125.

Erickson authored a textbook on sports vision, applying an evidence-based approach to assessment and treatment procedures as well as outcome expectations 126.

Maman, Gaurang, and Sandhu studied the effects of vision training on performance of collegiate tennis players. This was a prospective, randomized clinical trial that included a placebo and control group. The experimental group underwent eight weeks of vision training three days a week for 30 minutes each. The placebo group was instructed to watch televised tennis matches, while the control group was not given any training. At the end of eight weeks’ training, the pre-training evaluation protocol was repeated. Pre- and post-test results were obtained for reaction time, depth perception, accommodation, saccadic eye movements and tennis performance. The statistical analysis indicated significant improvement in all mentioned visual variables in the experimental group (p<0.001) and the placebo group (p<0.01), and non-significant results in the control group 127.

Clark and colleagues published research indicating that vision training can improve batting performance as well as depth judgement of baseball players at the collegiate level 128 129.

There is a significant body of work in the specific sports vision literature over the last 30 years, and there are studies suggesting additional work is justified, and considerable work is being done by Professor Paul Harris at the Southern College of Optometry in the USA.

Zwierko T (2015)130 in a study testing how binocular vision was influenced by an eye training program that may be used to improve individual's oculomotor function, showed that results of the retention testing conducted four weeks after the experiment confirmed the effectiveness of the vision training program. The results of the study suggest that binocular functions are trainable and can be improved by means of appropriate visual training.

40 | P a g e Conclusion

Sports vision is an integral part of everyday optometric care, involving assessment of visual dysfunctions, and prescription of spectacles, contact lenses and protective eyewear, where indicated. Deficient visual abilities may have an effect on sports performance, and can be treated with vision therapy.

41 | P a g e The Need for High Quality Research Studies

Barrett discusses “double-blind” studies and other well documented research protocols, implying that the absence of such methodologies in behavioural optometry approaches constitutes a flaw in its evidence base. In order to substantiate such claims, a detailed review of each piece of evidence is demanded.

The approach followed by Barrett might be legitimate if it were to have qualified the levels of evidence for each of the entities that he cited. A perfect example of how this is done is the review paper by Bowan (op cit) which categorizes five levels of evidence:

Level I randomized, double-blinded, controlled studies of adequate size.

Level II smaller, randomized, double-blinded, controlled studies with positive trends that may not be statistically significant.

Level III non-randomized controlled studies or cohort or case series studies.

Level IV expert opinions from acknowledged authorities 94.

Although high quality research studies at levels I and II are always welcome, any self- proclaimed “critical evaluation of evidence” that qualifies or discredits a methodology or treatment approach (such as Behavioural Optometry) would have to establish that the methodology or treatment approach against which it is being compared exhibits superior levels of evidence. This standard is clearly not met in Barrett’s review.

42 | P a g e A Brief Word About Evidence Based Practice

The discussion about the meaning and value of “evidence based practice” would occupy another review paper in its own right. However, we can be clear and confident in the view that it does not simply mean only practicing that which has been proven by research.

The most commonly used definition of Evidence-Based Practice (EBP) is from Professor David Sackett OC FRCS, a founder of the Oxford Centre for Evidenced Based Medicine and inductee to the Canadian Medical Hall of Fame. “EBP is “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of the individual patient. It means integrating individual clinical expertise with the best available external clinical evidence from systematic research.”131.132

Applying Sackett’s principles, an extensive review and discussion of evidence-based practice (EBP) utilized in clinical neuro-developmental and rehabilitative optometric vision therapy, and directliy supportive of behavioural optometry practice has recently been published 133.

On its web site, Duke University goes on to say, “EBP is the integration of clinical expertise, patient values, and the best research evidence into the decision making process for patient care. Clinical expertise refers to the clinician’s accumulated experience, education and clinical skills. The patient brings to the encounter his or her own personal preferences and unique concerns, expectations, and values. The best research evidence is usually found in clinically relevant research that has been conducted using sound methodology. (Sackett D, 2002)

43 | P a g e The evidence, by itself, does not make the decision, but it can help support the patient care process. The full integration of these three components into clinical decisions enhances the opportunity for optimal clinical outcomes and quality of life. The practice of EBP is usually triggered by patient encounters which generate questions about the effects of therapy, the utility of diagnostic tests, the prognosis of diseases, and/or the aetiology of disorders.”

It is very clear from the discussion presented here, that vision therapy qualifies as “evidence based practice”

44 | P a g e Final Conclusion

It is clear that Barrett’s review of vision therapy and behavioural optometry significantly suffers from evidential and discursive problems, and its use as evidence against current practice, and even knowledge at the time of publication, is very questionable.

In the ten years since Barrett’s paper was published, there has been much evidence produced to support the approach and methodology of behavioural optometrists. Even in the paper itself Barrett is largely supportive and concedes that there is evidence for vision therapy.

In some aspects, there is confusion and mistaken interpretation about the claims made by optometrists who use vision therapy, and many of the supporting academic work has been missed, or arose after publication. This discussion has not attempted to provide anything like a comprehensive list of works that underpin vision therapy and other methodologies. Our main purpose is to demonstrate that Barrett’s paper was unrepresentative and flawed at the time or publication, and has not been validated by evidence since, and in fact research since Barrett’s selective review has disproven many of his assertions, and comprehensively contradicted many of his conclusions. We have referred to more than 100 papers published by noted academics, senior clinicians and researchers, optometrists and ophthalmologists, from some of the best organisations in the world, which were either missed by Barrett, or have arisen since publication.

If there is a reasonable conclusion to be drawn from Barrett’s paper, it is that more research is needed, and no rational person would disagree. That could be said of any branch of science at any time.

To utilise Barrett’s work as evidence for invalidating behavioural optometry and vision therapy, is outdated, misleading and incorrect.

45 | P a g e References

1 (Birnbaum MH. Behavioral optometry: A historical perspective. J Am Optom Assoc 1994;65(4):255-64

2 Doyle MP. Vision therapy in the modern behavioral optometry practice: The history of vision therapy and contemporary approaches to case selection, case management, and delivery of treatment. Optometry and Visual Performance 2016;4(1):15-22

3 Kiely, P. M. and Slater, J. (2015), Optometry Australia Entry-level Competency Standards for Optometry 2014. Clinical and Experimental Optometry, 98: 65–89.

4 Schmitt EP. The Skeffington Perspective of the Behavioral Model 0f Optometric Data Analysis and Vision Care. AuthorHouse 2006.

5 Press LJ. Applied Concepts in Vision Therapy. 2nd ed. Santa Ana: Optometric Extension Program, 2008

6 Convergence Insufficiency Treatment Trial Investigator Group. Randomized clinical trial of treatments for symptomatic convergence insufficiency in children. Arch Ophthalmol 2008;126:1336-1349.

7 Westmana M, Liinamaaa MJ. Relief of asthenopic symptoms with orthoptic exercises in convergence insufficiency is achieved in both adults and children. Journal of Optometry. 2012 5, 62-67

8 Serna A. et al. Treatment of symptomatic convergence insufficiency with a home-based computer orthoptic exercise program. J AAPOS 2011;15:140-143

9 McGregor ML. Convergence insufficiency and vision therapy. Pediatr Clin North Am. 2014 Jun;61(3):621-30. doi: 10.1016/j.pcl.2014.03.010.

10 Sreenivasan V, Bobier WR. Increased onset of vergence adaptation reduces excessive accommodation during the orthoptic treatment of convergence insufficiency. Vision Res. 2015 Jun;111(Pt A):105-13. doi: 10.1016/j.visres.2015.04.001. Epub 2015 Apr 16.

11 Sreenisvasan publications: https://www.researchgate.net/profile/Vidhyapriya_Sreenivasan/publications Bobier publications: https://www.researchgate.net/profile/William_Bobier/publications

12 Gallaway M, Scheiman M. The efficacy of vision therapy for convergence excess. J Am Optom Assoc 1997; 68:81-6.

13 Scheiman M et al. Convergence Insufficiency Treatment Trial – Attention and Reading Trial (CITT-ART): Design and Methods. Vis Dev Rehabil. 2015 Oct; 1(3): 214–228.

14 Scheiman M, Gwiazda J, Li T. Non-surgical interventions for convergence insufficiency. Cochrane Database of Systematic Reviews. 2011;(3):CD006768.

15 Alvarez TL, Jaswal R, Gohel S, Biswal BB. Functional activity within the frontal eye fields, posterior parietal cortex, and cerebellar vermis significantly correlates to symmetrical vergence peak velocity: an ROI based, fMRI study of vergence training. Frontiers in Integrative Neuroscience 2104;8:219-230

46 | P a g e

16 Weisz, D. L. (1979) Clinical therapy for accommodative responses: transfer effects upon performance. J. Am. Optom. Assoc.50, 209–216

17 Hoffman, L. G. (1982) The effect of accommodative deficiencies on the developmental level of perceptual skills. Am. J. Optom. Physiol. Opt. 59,254–262

18 Aziz, S., Cleary, M., Stewart, H. K. and Weir, C. R. (2006) Are orthoptic exercises an effective treatment for convergence and fusion deficiencies? Strabismus 14,183–189.

19 Rouse, M. W. (1987) Management of binocular anomalies: efficacy of vision therapy in the treatment of accommodative deficiencies. Am. J. Optom. Physiol. Opt. 64,415–420

20 Grisham, J. D., Bowman, M. C., Owyang, L. A. and Chan, C.L. (1991) Vergence orthoptics: validity and persistence of the training effect. Optom. Vis. Sci.68,441–451

21 Sterner, B., Abrahamsson, M. and Sjöström, A. (1999). Accommodative facility training with a long term follow up in a sample of school aged children showing accommodative dysfunction. Doc. Ophthalmol. 99,93– 101

22 Ciuffreda, K. J. (2002) The scientific basis for and efficacy of optometric vision therapy in nonstrabismic accommodative and vergence disorders. Optometry 73,735–762

23 Cooper, J., Feldman, J., Selenow, A., Fair, R., Buccerio, F., MacDonald, D. and Levy, M. (1987) Reduction of asthenopia after accommodative facility training. Am. J. Optom. Physiol. Opt. 64,430–436.

24 Sterner, B., Abrahamsson, M. and Sjostrom, A. (2001) The effects of accommodative facility training on a group of children with impaired relative accommodation – a comparison between dioptric treatment and sham treatment. Ophthalmic Physiol. Opt. 21,470–476

25 Brautaset, R., Wahlberg, M., Abdi, S. and Pansell, T. (2008). Accommodation insufficiency in children: are exercises better than reading glasses? Strabismus 16,65–69

26 Scheiman M, Cotter S, Kulp MT, Mitchell GL, Cooper J, Gallaway M, Hopkins KB, Bartuccio M, Chung I; Convergence Insufficiency Treatment Trial Study Group. Treatment of accommodative dysfunction in children: results from a randomized clinical trial. Optom Vis Sci. 2011 Nov;88(11):1343-52. doi:0.1097/OPX.0b013e31822f4d7c.

27 Scheiman M et al. Treatment of accommodative insufficiency in children:results from a randomized clinicial trial. Optom Vis Sci. 2011 Nov;88(11):1343-52

28 Cooper JS, Burns CR, Cotter SA, Daum KM, Griffin JR, Scheiman MM. Optometric Clinical Practice Guideline: Care of the Patient With Accommodative and Vergence Dysfunction - Reference Guide for Clinicians. St. Louis, MO: American Optometric Association, 2011.

29 Wick B. Accommodative esotropia: efficacy of therapy. J Am Optom Assoc. 1987 Jul;58(7):562-6

30 Ziegler D, Huff D, Rouse MW. Success in strabismus therapy: a literature review. J Am Optom Assoc. 1982 Dec;53(12):979-83.

31 Hatt, S. and Gnanaraj, L. (2006) Interventions for Intermittent Exotropia. Cochrane Database Syst. Rev., Art. No.:CD003737. doi: 10.1002/14651858.CD003737.pub2. 47 | P a g e

32 Hatt SR, Gnanaraj L. Interventions for intermittent exotropia. Cochrane Database Syst Rev 2013 May 31;(5):CD003737. doi: 10.1002/14651858.CD003737.pub3.

33 Elliott S, Shafiq A. Interventions for infantile esotropia. Cochrane Database Syst Rev. 2013 Jul 29;(7):CD004917.

34 Press LJ. Applied Concepts in Vision Therapy. 2nd ed. Santa Ana: Optometric Extension Program, 2008. pp.191-2

35 Flax N, Duckman RH. Orthoptic treatment of strabismus. Journal of the American Optometric Association, 49: 1353-1361, 1978.

36 Krumholtz I, FitzGerald D. Efficacy of treatment modalities in refractive amblyopia. Journal of the American Optometric Association, June; 70(6):399-404, 1999.

37 Coffey B, Wick B, Cotter S, et al. Treatment options in intermittent exotropia: a critical appraisal. Optometry and Vision Science, 69: 386-404, 1992

38 Levi DM , Li RW Perceptual learning as a potential treatment for amblyopia: A mini-review. Vision Research. 49 (2009) 2535–2549

39 Alotaibi AG, Fawazi SM, Alenazy BR, Abu-Amero KK. Outcomes of 3 hours part-time occlusion treatment combined with near activities among children with unilateral amblyopia. Saudi Med J. 2012 Apr;33(4):395-8.

40 Wong AM. New concepts concerning the neural mechanisms of amblyopia and their clinical implications. Can J Ophthalmol 2012,Oct;47(5):399-409.

41 Press LJ. Electronic games and strabismus therapy. J Optom Vis Dev 1981;12:35-9.

24 Hess RF, Thompson B, Black JM, Machara G, Zhang P, Bobier WR, An iPod treatment of amblyopia: an updated binocular approach. Cooperstock J.Optometry. 2012 Feb 15;83(2):87-94.

43 Webber A , L, Wood JM, Thompson B. Fine motor skills of children with amblyopia improve following binocular treatment. Invest Ophthalmol Vis Sci 2016;57:4713-4720

44 Rutstein RP, Cotter SA, Daum KM, Molzlin RL, Ryan JM. Optometric Clinical Practice Guideline - Care of the Patient with Strabismus: Esotropia and Exotropia. St. Louis, MO: American Optometric Association 2011

45 Horner SH. The use of yoked prisms to enhance visual training. Santa Ana, CA: Optometric Extension Program, Curriculum II, Oct 1972 - Sept 1973.

46 Margach CB. Yoked Prisms: Part I. Santa Ana, CA: Optometric Extension Program, Curriculum II, Feb 1980: 25-29

47 Margach CB. Yoked Prisms: Part II. Santa Ana, CA: Optometric Extension Program, Curriculum II, Mar 1980: 31-34

48 Robert A. Kraskin. Lens Power in Action The uniqueness of optometry.: Santa Ana CA.Optometric Extension Program, Curriculum II, Oct 1981-Sepet 1983

49 Kaplan, Melvin. Vertical Yoked Prisms. s.l. : Optometric Extension Program, 1988. 48 | P a g e

50 Press LJ. Lenses and behavior. J Optom Vis Devel 1990;21L5-17

51 Harris, Paul A. The Behavioral Use of Prisms. [book auth.] Anne Barber. Vision Therapy - Tools of Behavioral Vision Care: Prisms. s.l. : Optometric Extension Program, 1996, pp. 1-32

5252 Sheedy JE, Parsons SD. Vertical yoked prism--patient acceptance and postural adjustment. Ophthalmic Physiol Opt 1987;7(3):255-57

53 Sheedy JE, Parsons SD. Vertical yoked prism--patient acceptance and postural adjustment. Ophthalmic Physiol Opt 1987;7(3):255-57

54 Padula, William V. A Behavioral Vision Approach for Person with Physical Disabilities. s.l. : Optometric Extension Program, 1988.

55 Harris, Paul A. The Use of Lenses to Improve Quality of Life Following Brain Injury. [book auth.] Lisa Harvey & Penelope Suter. Vision Rehabilitation - Multidisciplinary Care of the Patient Following Brain Injury. s.l. : CRC Press, 2011.

56 William V. Padula, OD et al. Neuro-Visual Processing Rehabilitation: An Interdisciplinary Approach. s.l. : Optometric Extension Program, 2012.

57 Kokotas, Vassilis (2016). The effects of yoked prisms on body posture and egocentric perception in a normal population. PhD thesis, Aston University. http://eprints.aston.ac.uk/28744/

58 Lazarus, S. M. (1996) The use of yoked base-up and base-in prism for reducing eye strain at the computer. J. Am. Optom. Assoc. 67, 204–208.

59 Fox RS. A Rationale for the Use of Prisms in the Vision Therapy Room. J Behav Optom 2011;22(5):126-29

60 Begotka B. Improving Orientation with Yoked Prism. Optom Vis Perf 2014;2(2):83-4.

61 Wong et al., (2002) Effects of using prismatic lenses on posture of patients with adolescent idiopathic scoliosis measured by 3D motion analysis. Rehabilitation Engineering Centre, The Hong Kong Polytechnic University, Kowloon, China. Prosthetics and Orthotics International (Impact Factor: 1.04). 09/2002; 26(2):139- 53.

62Howell ER. In: Chen, Ai-Hong, Leat SJ. Eds. Pediatric Vision Care. Current Practice and Future Challenges. McGraw Hill Eduaction Asia 2015. Challenges and Controversies in Paediatric Vision Care: B: Page numbers to be inserted

63 Huang MA , Ciuffreda KJ. Short-term adaptation to vertical yoked prisms. Optom Vis Sci 2006;83:E242-48.

64 Michel C, Rossetti Y, Rode G, Tiikete C. After-effects of visuo-manual adaptations to prisms on body posture in normal subjects. Exp Brain res 2003;148:219-26.

65 Redding GM , Wallace B. Prism adaptation and unilateral neglect : Review and analysis. Neuropsychologia 2006;44:1-20.

66 Jacquin-Courtois S, Rode G, Pisella L, Boisson D, Rossetti Y. Wheel-chair driving improvement following visuo-manual prism adaptation. Cortex 2008;44:90-96. 49 | P a g e

67 Allison CL, Gabriel H, Schlange D, Fredrickson S. An Optometric approach to patients with sensory integration dysfunction. Optom 2007;78:644-51.

68 Padula WV. Neuro-optometric Rehabilitation, 3rd Edition. Santa Ana CA: Optometric Extension Program, 2000.

69 Caldwell CH, Reyes-Cabrera E. A Deliberate Set of Examinations and the Application of Yoked Prisms in the Treatment of Visual Midline Shift Syndrome: A Case Report. Optom Vis Perf 2015;3(6):291-97.

70 Padula WV, Subramanian P, Spurling A, Jenness J. Risk of fal l (RoF) intervention y affecting visual egocenter by gait analysis and yoked prisms. Neurorehabilitation 2015;37(2):305-14.

71 Bansal S, Han E, Ciuffreda KJ. Use of yoked prisms in patients with acquired brain injury: a retrospective analysis. Brain Inuury 2014;28(11):1441-6.

72 Forrest EB. Stress and Vision. Santa Ana, CA: Optometric Extension Program, 1988.

73 Werner DL, Press LJ. Clinical Pearls in Refractive Care. Boston: Butterworth Heinemann, 2002.

74 Press LJ. Physiological effects of plus lens application. Am J Optom Physiol Opt 1985;62(6): 392-97.

75 Dynamic retinoscopy. Guyton DL, O’Connor GM. Curr Opin Ophthalmol. 1991 Feb;2(1):78-80.

76 Dynamic retinoscopy: the missing data. Hunter DG. Surv Ophthalmol. 2001 Nov-Dec;46(3):269-74

77 Quaid P, Simpson T. Association between reading speed, cycloplegic refractive error, and oculomotor function in reading disabled children versus controls. Graefes Arch Clin Exp Ophthalmol (2013) 251:169–187.

78 Larrabee PE Jr, Jones FR. Behavioral effects of low plus lenses. Percept Mot Skills. 1980 Dec;51(3 Pt 1):913-4.

79 Greenspan SB. Effect of children’s near point lenses upon body posture and performance. Am. J. Optom., 1970

80 Greenspan SB references: http://www.ncbi.nlm.nih.gov/pubmed/?term=Greenspan%20SB%5BAuthor%5D&cauthor=true&cauthor_uid= 802931

81 Iyer J, and Harris P. The Effect of Low Plus Lenses on Reading Rate and Comprehension. Optometry and Visual Performance. 2013, Vol 1(2).

82 Goss DA. Clinical accommodation and heterophoria findings preceding juvenile onset of myopia. Optom. Vis. Sci., 1991

83 J. Gwiazda, L. Hyman, et al. A randomized clinical trial of progressive addition lenses versus single vision lenses on the progression of myopia in children. Invest. Ophthalmol. Vis. Sci., 2003

84 Goss, D. A. (1991) Clinical accommodation and heterophoria findings preceding juvenile onset of myopia. Optom. Vis. Sci. 68, 110–116

85 Fulk GW, Cyert LA, Parker DE. A randomised trial of the effect of single-vision vs. bifocal lenses on myopia progression in children with esophoria. Optom. Vis. Sci, 2000. 50 | P a g e

86 Goss DA, Rainey BR.. Control of myopia with nearpoint plus as a function of near phoria: literature review and additional prospective data. J Behav Optom 2009;20:115-122.

87 Huang J, Wen D, Wang Q, et al. Efficacy Comparison of 16 Interventions for Myopia Control in Children: A Network Meta-analysis.Ophthalmology. 2016 Apr;123(4):697-708. doi: 10.1016/j.ophtha.2015.11.010. Epub 2016 Jan 27.

88 Gifford K.Myopia control with contact lenses in practice. http://www.mivision.com.au/myopia-control-with- contact-lenses-in-practice/

89 Donahue, S. P. (2004) How often are spectacles prescribed to normal preschool children? J. AAPOS 8, 224– 229.

90 Robaei, D., Kifley, A., Rose, K. A. and Mitchell, P. (2006). Refractive error and patterns of spectacle use in 12- year-old. Australian children. Ophthalmology 113, 1567–1573.

91 Ip, J. M., Robaei, D., Rochtchina, E. and Mitchell, P. (2006). Prevalence of eye disorders in young children with eyestrain complaints. Am. J. Ophthalmol. 142, 495–497.

92 Filips, R. (2008) Low plus lenses for children. Ophthalmology 115, 222–223.

93 Creavin AL et al. Ophthalmic abnormalities and reading impairment. Pediatrics 2015;135:1057-65

94 Bowan MD. Learning disabilities, dyslexia and vision: a subject review. A rebuttal, literature review and commentary. Optometry 2002; 73: 553 – 75

95 Lack D. Another joint statement regarding learning disabilities, dyslexia, and visiondA rebuttal. Optometry 2010;81(10):533-43

96 Position Paper on Optometric Care of the Struggling Student For parents, educators, and other professionals. American Academy of Optometry 2013. Available online at: http://www.aaopt.org/sites/default/files/Revised%20Oct%2018_BVPPO_Position_paper%20AAO%20website %20formatFINAL.pdf

97 Garzia RP, Borsting EJ, Nicholson SB, Press LJ, Scheiman MM, Solan HA. Optometric Clinical Practice Guideline: Care of the Patient with Learning Related Vision Problems. St. Louis: American Optometric Association, 2008

98 Hong CL, Press LJ. Visual Factors in childhood Behavioral disorders. California Optometry, July/August 2009, Volume 36, Number 4, Pages 46-54

99 Tiadi A, Girard CL, Peyre H, Bui-Quoc E, Bucci MP. Immaturity of Visual Fixations in Dyslexic Children. Front Hum Neurosci 2016;10:58. http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4756100/

100 Franceschini S, Gori S, Ruffino M, Pedrolli K, Facoetti A. A Causal Link between Visual Spatial Attention and Reading Acquisition. Current Biology 2012;22(9):814-19. http://www.cell.com/current-biology/pdf/S0960- 9822(12)00270-9.pdf

101 Vidayasagar TA, Pammer K. Dyslexia: a deficit in visuo-spatial attention, not in phonological processing. Trends Cogn Sci 2010;14(2):57-63. 51 | P a g e

102 Ortiz R, Estevez A, Muneton M, Dominquez C. Visual and auditory perception in preschool children at risk for dyslexia. Res Devel Disabil 2014;35(11):2673-80.

103 Creavin AL, Lingam R, Steer C, Williams C. Ophthalmic abnormalities and reading impairment. Pediatrics. 2015 Jun;135(6):1057-65. doi: 10.1542/peds.2014-3622.

104 Handler SM, Fierson WM; Section on Ophthalmology; Council on Children With Disabilities; American Academy of Ophthalmology; American Association for Paediatric Ophthalmology and Strabismus; American Association of Certified Orthoptists. Learning disabilities, dyslexia, and vision. Paediatrics. 2011;127(3). Available at: www.pediatrics.org/cgi/content/full/127/3/e818

105 Creavin AL, Lingam R, Steer C, Williams C. Ophthalmic abnormalities and reading impairment. Pediatrics. 2015. Vol 135, 6; 1057-65. www.pediatrics.org/cgi/doi/10.1542/peds.2014-3622 Already cited

106 Van Rijn LJ, Krijnen JS, et al. Spectacles may help improve reading speed in Children with hyperopia. Optom Vis Sci. 2004. VOl 91, 4; 1-7

107 Simons HD, Gassler PA. Vision anomalies and reading skill: A meta-analysis of the literature. AM J Optom Physiolo Opt 1988; 65; 893-904.

108 Quaid P, Simpson T. Association between reading speed, cycloplegic refractive error, and oculomotor function in reading disabled children versus controls. Graefes Arch Clin Exp Ophthalmol. 2013 Jan;251(1):169- 87. doi:10.1007/s00417-012-2135-0. Epub 2012 Aug 29.

109 Ciuffreda, KJ. The Scientific Basis for and Efficacy of Optometric Vision Therapy in Nonstrabismic Accommodative and Vergence Disorders. Optometry 2002; 73:735-62.

110 Griffin JR, Christenson GN, Wesson MD. Erickson GB. Optometric Management of Reading Dysfunction. Boston: Butterworth-Heinemann 1996

111 Solan HA. Models of Reading Disability and Their Implications, In GK Hung and KJ Ciuffreda, eds. Models of the Visual System. New York: Springer Science, 2002:679-710.

112 Solan HA. Visual perceptual factors in reading: Clinical implications of some recent optometric research. J Behav Optom 1990;1(3):59-64.

113 Solan HA, Larson S Shelley-Tremblay J, Ficarra A, Silverman M. Role of visual attention in cognitive control of oculomotor readiness in students with reading disabilities. J Learn Disabil 2001;34(2):107-18.

114 Rafique S, Northway N. Relationship of ocular accommodation and motor skills performance in developmental coordination disorder. Hum Mov Sci 2015 Aug;42:1-

115 Crawford, S. G. and Dewey, D. (2008) Co-occurring disorders: a possible key to visual perceptual deficits in children with developmental coordination disorder? Hum. Mov. Sci. 27,154–169.

116 Hurst, C. M., Van de Weyer, S., Smith, C. and Adler, P. M.(2006) Improvements in performance following optometric vision therapy in a child with dyspraxia. Ophthalmic Physiol. Opt. 26, 199–210.

117 Coetzee D, Pienaar AE. The effect of visual therapy on the ocular motor control of seven- to eight-year-old children with developmental coordination disorder (DCD). Res Dev Disabil. 2013 Nov;34(11):4073-84. doi: 10.1016/j.ridd.2013.08.036. Epub 2013 Sep 19 52 | P a g e

118 Robert MP, Ingster-Moati I, Albuisson E, Cabrol D, Golse B, Vaivre-Douret L. Vertical and horizontal smooth pursuit eye movements in children with developmental coordination disorder. Dev Med Child Neurol. 2014 Jun;56(6):595-600. doi: 10.1111/dmcn.12384. Epub 2014 Jan 31. PMID:24479437

119 Arents A, Berger Martinet A, Blanc S, Niessen F. Pediatric ophthalmologic and orthoptic evaluation of the dyspraxic child. J Fr Ophtalmol. 2012 Nov;35(9):651-60. doi: 10.1016/j.jfo.2011.11.012. Epub 2012 Sep 19.

120 Granet, D. B., Gomi, C. F., Ventura, R. and Miller-Scholte, A. (2005) The relationship between convergence insufficiency and ADHD. Strabismus 13, 163–168.

121 Gomes A, Barbosa A. Convergence Insufficiency In Children With Attention Deficit Hyperactivity Disorder. Arch Dis Child 2014;99:A517 doi:10.1136/archdischild-2014-307384.1439

122 Puig MS, Zapata LP, Puigcerver L, Iglesias NE, Garcia CS, Romeo A, Crespillo JC, Super H. Attention-Related Eye Vergence Measured in Children with Attention Deficit Hyperactivity Disorder. PLoS One 2015;10(12):e0145281.

123.Lee SH, Moon BY, Cho HG. Improvement of Vergence Movements by Vision Therapy Decreases K-ARS Scores of Symptomatic ADHDChildren. J Phys Ther Sci. 2014 Feb;26(2):223-7. doi: 10.1589/jpts.26.223. Epub 2014 Feb 28

124 Knudson D. Kluka DA. The Impact of Vision and Vision Training on Sport Performance. J Phys Ed Recr Dance 1997;68(4):17-24

125 Schwab S, Memmert D. The Impact of a Sports Vision Training Program in Youth Field Hockey Players. J Sports Sci Med 2012;11(4):624-31.

126 Erickson G. Sports Vision: Vision Care for the Enhancement of Sports Performance. St. Louis: Butterworth- Heinemann/Elsevier, 2007.

127 Maman P, Gaurang S, Sandhu JS. The effects of vision training on performance in tennis players. Serb J Sport Sci 2011;5(1):11-16.

128 Clark JF, Ellis JK, Bench J, Khoury J, Graman P. High-Performance Vision Training Improves Batting Statistics for University of Cincinnati Baseball Players. PLoS One 2012;7(1):e29109.http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0029109

129 Clark JF, Graman P, Ellis JK. Depth perception improvement in collegiate baseball players with vision training. Optom Vis Perf 2015;3(2):106-15.

130Zwierko T, Puchalska-Niedbał L, Krzepota J, Markiewicz M, Woźniak J, Lubiński W. The Effects of Sports Vision Training on Binocular Vision Function in Female University Athletes. J Hum Kinet. 2015 Dec 30;49:287-96. doi: 10.1515/hukin-2015-0131. eCollection 2015.

131 Sackett DL, Rosenberg WM, Muir Gray JA, Haynes RB, Richardson WS. Evidence based medicine: what it is and what it isn't BMJ 1996;312:71

132 Duke University Medical Centre. http://guides.mclibrary.duke.edu/c.php?g=158201&p=1036021

133 Peachey GT, Peachey P. Optometric vision therapy for visual deficits and dysfunctions: A suggested model for evidence-based practice. Vision Dev & Rehab 2015;1(4):290-336. 53 | P a g e