Dyslexia is a neurological disorder with genetic origin that affects a person’s word processing ability, their spelling, writing, comprehension and reading, and results in poor academic performance. As a result, optometrists are consulted for assistance with the diagnosis and treatment of a possible vision condition. Optometrists are able to assist with treatment as part of a multidisciplinary management approach, where optometric support is necessary. International studies have indicated that up to 20% of Caucasian school children are affected by dyslexia, while there are no similar figures for African children. Studies have been done to assess the extent of visual defects among Caucasian dyslexics, but not among African dyslexic children. The aim of the study is therefore to determine the prevalence of vision conditions in an African South African population of dyslexic school children, and to investigate the relationship between dyslexia and vision. The possible relationship between dyslexia and vision conditions has been recognized as an important area of study, resulting in research being conducted in many countries. Studies have been undertaken by optometrists and ophthalmologists, who differ in their approach and attitude on how vision conditions affect dyslexia. A review of the literature revealed three broad areas of vision that may impact on reading ability, these being acuity defects, binocular vision and ocular pathology. Acuity defects consist of visual acuity and refractive error. Areas of binocular vision evaluated in the literature include near point convergence, heterophoria, strabismus, accommodative functions, vergence facility and reserves. Hyperopia was the only vision variable that was found to be consistently associated with difficulties with reading, but not causally while findings on other variables were inconclusive. However, all the studies acknowledged the complexity of the condition, and the need for a comprehensive multidisciplinary management approach for its diagnosis and management. The study was undertaken in the city of Durban, South Africa, using a case-control study of two groups of African school children between the ages of 10 and 15. Both study groups consisted of 31 children of normal intelligence, who were matched in gender, race and socio-economic status. The case group attended a school for children with learning disabilities, while the control group attended a mainstream school. At the time of the study, only one school catered for African children with learning disabilities, and only 31 of its pupils were diagnosed with dyslexia. Ethical approval was obtained from the University of KwaZulu-Natal; permission to undertake the study in the identified schools was obtained from the Department of Education, and the school principals consented on behalf of the learners, as it was not always possible to reach the individual parent. The researcher (an optometrist) visited both schools by appointment where rooms were made available to do the testing, and the tests were explained to all participants. The LogMar Acuity Charts were used to assess visual acuity, and static retinoscopy was used to assess refractive error. Binocular vision was tested using the cover test for ocular alignment, the Hirschberg test for strabismus, RAF rule for near point of convergence, ± 2 D flipper lenses for accommodation facilities, Donder’s push up methods, using the RAF rule for amplitude of accommodation, plus and minus lenses for relative accommodation, monocular estimation technique for accommodation posture, and prism bars for vergence reserves. Ocular pathology was assessed using a direct ophthalmoscope. The dyslexic group presented with the following: Refractive errors: hyperopia 6.5%, myopia 6.5%, astigmatism 10%, anisometropia 6.5%, remote near point of convergence 33%, esophoria at near 3%, exophoria at near 9.5%, accommodative infacility 54% and lag of accommodation 39.28%. The dyslexic group had relatively reduced fusional reserve compared to the control group. The control group presented with the following: Refractive errors: hyperopia 3%, astigmatism 13%, anisometropia 6.5%, remote near point of convergence 48%, esophoria at near 0%, exophoria at near 0%, accommodative infacility 33% and lag of accommodation 41.93%. The prevalence of a remote NPC was higher in the control group than in the dyslexic group and there was a statistically significant difference between the two groups: NPC break (p=0.049) and recovery (p=0.046). The prevalence of poor binocular accommodation facility at near was higher in the dyslexic group than in the control group and there was a statistically significant difference between the two groups (p = 0.027). Vision defects such as hyperopia, astigmatism, accommodation lag, convergence insufficiency, poor near point of convergence and accommodative infacility were present in the dyslexic pupils, but they were no more at risk of any particular vision condition than the control group. This study provided the prevalence of vision conditions in a population of African dyslexic children in South Africa, the only vision variable that was significantly more prevalent in the dyslexic population being the binocular accommodation facility at near, although the study was unable to find a relationship between dyslexia and vision. The statistically significant difference may not imply clinical significance due to the small sample size. However, it is recommended that any vision defects detected should be appropriately compensated for as defective vision can make reading more difficult for the dyslexic child. The sample size may have been a limitation; however, this was comparable with studies reviewed, most of which had sample sizes of less than 41. Due to the range of possible ocular conditions that could affect dyslexia, it is recommended that a larger sample size be used to ensure more conclusive results. Testing for relative accommodation with a phoropter would provide more accurate results, and accommodation facility and fusional reserves would be better assessed with suppression control. The study provides information and an indication of research needs regarding the prevalence of vision defects in an African South African population of dyslexic children. / Thesis (M.Optom.)-University of KwaZulu-Natal, Westville, 2010.

International debate exists between several disciplines about when and how young people's vision should be screened and the relationship between vision and learning. This thesis is concerned with whether adolescents' acuity and binocular functioning can be accurately screened by a registered nurse (RN) and the impact of such a Primary Health Care (PHC) initiative on the participants. The aims of this study include to: screen the monocular and binocular vision of students aged 12 - 13 years; determine the accuracy and efficacy of the screening process; gain insight into the impact of undetected visual problems on the students' experiences with schoolwork and leisure activities; determine why young people are compliant or non-compliant with optometric intervention; and to gain insight into the impact of optometric interventions. / The RN screened 222 students in Year 8 at an Adelaide secondary school and 145 of them had follow-up optometric examinations. Several months later 25 students with poor vision were interviewed about their experiences at Primary School and whether they had followed through with the suggested optometric treatment. They also completed a questionnaire about eyestrain symptoms. Case studies were created from the quantitative and qualitative data and a Health Technology Assessment framework (HTA) used to analyse the data in a manner congruent with the study aims. This framework allowed for the social impact of the vision screening battery and optometric care to be discussed and the health and educational outcomes to be synthesized. / A large percentage (72.4%) of those who had optometric examinations had one or more vision problems. The screening battery had a sensitivity of 94.6%, specificity of 66%, Predictive Value Positive 82.9%, and Predictive Value Negative 87.5%. The case study data illustrate the complexity of the vision-learning link and the educational and social benefits to numbers of students who received optometric care. For some students, poor near vision resulted in a below-average reading performance. Poor vision was also associated with slow verbal responses, puzzled facial expressions, inattention and disruptive behaviours that resulted in school suspension. These clinical features tended to be interpreted by teachers as indicating that a student was academically less-able. Two male participants were found to have extremely poor vision and both had histories of disruptive behaviour and school failure. The RN intervention and optometric treatment enabled them to become successful learners for the first time and impacted positively on their psychological and emotional health. A number of students who were achieving excellent grades were also helped by vision care that reduced their eyestrain. / The conclusion is reached that poor vision should be recognised as a sensory disability and that universal school vision screening which includes aspects of binocularity is important for students' well-being. Subtle changes to improve the accuracy of the RN screening battery are suggested. An RN is ideally suited to be the screener and liaise between optometrists, teachers, students and parents/guardians, in order to encourage follow-up care. / Finally, healthcare and education systems need to be closely allied so that the outcomes of PHC interventions can be measured in educational and social terms rather than simply by morbidity statistics. / Thesis (PhDNursing)--University of South Australia, 2005.

Thesis (Ph.D.)--University of Adelaide, School of History and Politics, Discipline of Politics, 2004. / Title from opening screen; viewed 19 May 2005. "August 2004." Includes bibliographical references. Also available in print format.

Thesis (Ph.D.)--University of Adelaide, School of History and Politics, Discipline of Politics, 2004. / "August 2004." Includes bibliographical references (leaves 322-345). Also available electronically via the Australian Digital Theses Program.

Thesis (Ph. D.)--University of Sydney, 2008. / Title from title screen (viewed 18 June 2008). Submitted in fulfilment of the requirements for the degree of Doctor of Philosophy to the Department of Clinical Ophthalmology and Eye Health, Faculty of Medicine. Degree awarded 2008; thesis submitted 2007. Includes bibliographical references. Also available in print form.

Thesis (MSD (Play Therapy))--University of Pretoria, 2003. / Includes bibliographical references.

Thesis (Ph. D.)--University of California, San Diego and San Diego State University, 1997. / Vita. Includes bibliographical references (leaves 161-169).

Thesis (M.A.)--York University, 2005. Graduate Programme in Psychology. / Typescript. Includes bibliographical references (leaves 58-62). Also available on the Internet. MODE OF ACCESS via web browser by entering the following URL: http://gateway.proquest.com/openurl?url%5Fver=Z39.88-2004&res%5Fdat=xri:pqdiss &rft_val_fmt=info:ofi/fmt:kev:mtx:dissertation&rft_dat=xri:pqdiss:MR11906

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