Research and Reviews

A common finding among individuals with Dyslexia, Developmental Coordination Disorders, Dyspraxia, Meares-Irlen Syndrome, Visual Stress, Migraine, Brain Injury, Multiple Sclerosis, Brain Injury and Autism is reading difficulties. The Visual aspects of reading difficulty includes the Refractive Aspects (Eyesight – How clear does the eye see?), Mechanical Aspects (Eye Tracking, Eye Teaming, Eye Focusing – How is the movement quality of the eyes?) and Perceptual Aspects (Visual Perceptual – How does the Visual System understand/interpret what is shown?) Visual discomfort affects reading by reducing accuracy and adversely affecting motivation because reading is uncomfortable, which in turn affects concentration, eventually affecting how much knowledge they acquire.

Under 3.3 Vision problems and teaching, the authors explained that all visual sensory and ocular motor functions (Eye Tracking, Eye Teaming, Eye Focusing) are connected in a visual circle where the eye motor capacities influence sensory and perceptual functions (Visual Perceptual – How does the Visual System understand/interpret what is shown?) and vice versa. Under 4. Impact of visual problems on the reading process, in a study of nearly 400 schoolchildren, between 8 and 15 years, only 54% were found to have normal accommodation (Eye Focusing) and convergence (Eye Teaming). These findings supports the connection between poor eye movement and reading difficulties.

Numerous clinical and research studies have shown that good visual abilities are beneficial to learning to read and to read with understanding. Children with normal eyesight (20/20) can have visual problems which affect how their eyes focus, team together, or move along a line of print when reading. These learning-related vision problems cause children to struggle and can result in their being mislabeled as learning disabled or having Attention Deficit Hyperactivity Disorder (ADHD).

This research indicates there are significant associations between reading speed, refractive error, and in particular vergence facility (Eye Teaming). It appears sensible that students being considered for reading specific IEP status should have a full eye examination (including cycloplegia), in addition to a comprehensive binocular vision evaluation (To assess oculomotor functional performance in Eye Tracking, Eye Teaming and Eye Focusing).

A comprehensive optometric examination should be indicated for any child who is having trouble reading. These visual skills, Visual acuity, Visual Fixation, Accommodation (Eye Focusing), Binocular Fusion, Saccades (Eye Tracking), Convergence (Eye Teaming), Field of vision and Form perception should be evaluated during the exam.

The authors report an apparent three-fold greater incidence of ADHD among patients with CI when compared with the incidence of ADHD in the general US population (1.8-3.3%). They also note a seeming three-fold greater incidence of CI in the ADHD population. This may simply represent an association and not be a causative relationship. Until further studies are performed, however, patients diagnosed with ADHD should be evaluated to identify the small subset that may have CI -- a condition that responds well to treatment at home.

A Joint Organizational Policy Statement of the American Academy of Optometry and the American Optometric Association

The findings suggest that deficits in visual function (Eye Tracking, Eye Teaming and Eye Focusing) are far more prevalent in school-aged children with developmental dyslexia than in typical developing readers, but the possible cause and clinical relevance of these deficits are uncertain. Further study is needed to determine the extent to which treating these deficits can improve visual symptoms and/or reading parameters.

The findings observed reduced monocular and binocular Near Point of Accommodation (Eye Focusing) in dyslexic children and recommend that this function should be assessed by an optometric clinician in children with dyslexia.

A higher proportion of individuals with dyslexia presented with optometric problems such as hypermetropia (Longsightedness) and accommodation insufficiency (Eye Focusing weakness) compared to controls. Untreated optometric disorders were present in both children and adults with dyslexia. The results strongly suggest that an optometric examination should be included in the management of this condition.

The College of Optometrists in Vision Development recommends a comprehensive evaluation which includes a thorough “eye” examination of structure and health, and a thorough “vision” examination of functions which are necessary to process visual information meaningfully. This comprehensive evaluation of vision leads to recommended management strategies including vision therapy, the application of lenses and prisms, and/or appropriate referral to other professionals.

42 studies were included in the narrative synthesis with 35 studies in the meta-analyses (3,250,905 participants). Meta-analytic evidence of increased risk of astigmatism, hyperopia, strabismus, unspecified vision problems and reduced near point of convergence (Weak Eye Teaming); increased lag and variability of the accommodative response (Weak Eye Focusing); and increased self-reported vision problems in people with ADHD compared to those without ADHD. We also found meta-analytic evidence of no differences between people with and without ADHD on retinal nerve fiber layer thickness and refractive error.

ADHD is associated with some self-reported and objectively ascertained functional vision problems, but not with structural alterations of the eye.

In this large nationally representative sample (75,171 children), the prevalence of ADHD was greater among children with vision problems not correctable with glasses or contacts. The association between vision problems and ADHD remains even after adjusting for other factors known to be associated with ADHD.

The results from this preliminary study suggest that school-aged children with symptomatic accommodative dysfunction or CI have a higher frequency of behaviors related to school performance and attention as measured by the CPRS-R:S.

Current research suggests that office‐based vergence/accommodative therapy with home reinforcement is more effective than home‐based pencil/target push‐ups or home‐based computer vergence/accommodative therapy for children. In adults, evidence of the effectiveness of various non‐surgical interventions is less clear.

Fifty-three primary school students with learning difficulty (including autism spectrum disorder, attention-deficit/hyperactivity disorder, specific learning disorder, specific language impairment and borderline intellectual functioning) were recruited and randomly assigned to either the Eye-tracking Training group or the after-school remediation class. Children who received the eye-tracking training, not those in the control group, showed a significant improvement in memory as measured by the delayed recall. In addition, the Eye-Tracking Training group showed significantly faster learning than the control group. Also, the two groups showed a significant improvement in their reading abilities. In sum, eye-tracking training may be effective training for enhancing the learning and memory of children with learning difficulties.

In an open trial, attention and internalizing problems improved significantly following treatment for CI.

For nearly 75 years, optometric vision therapy has been an important mode of therapy for both children and adults who manifested a range of nonstrabismic accommodative and vergence disorders. In this article, the scientific basis for, and efficacy of, optometric vision therapy in such patients will be discussed. Using bio-engineering models of the oculomotor system as the conceptual framework, emphasis will be focused on studies that used objective recording techniques to directly assess therapeutically related changes in oculomotor responsivity. The findings clearly support the validity of optometric vision therapy. Furthermore, the results are consistent with the tenets of general motor learning.

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