Visual factors and dyslexia: A research review

Wajuihian, S. O.; Naidoo, Kovin

doi:10.4102/aveh.v69i2.131

Cited by 4 publications

(6 citation statements)

References 29 publications

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“…Invariably, most school vision screenings are inadequate as most eye tests performed focus on visual acuity and refractive errors 7 giving less emphasis to visual parameters related to NVAs. Near vision anomalies have various negative consequences [8][9][10][11][12][13][14][15][16][17] . Convergence insufficiency (CI) has been associated with attention deficit hyperactivity disorder (ADHD) [8][9][10][11] , anxiety, emotional and social problems [13][14] and lowered academic achievements [14][15] .…”

Section: Introductionmentioning

confidence: 99%

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Near vision anomalies in Black high school children in Empangeni, South Africa: A pilot study

Wajuihian

Hansraj

2014

African Vision and Eye Health

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Background: The ability to read efficiently and comfortably is important in the intellectual development and academic performance of a child. Some children experience difficulties when reading due to symptoms related to near vision anomalies. Aim: To explore the feasibility of conducting a large study to determine the prevalence, distribution and characteristics of near vision anomalies in high school children in Empangeni, South Africa. Methods: The study was a cross sectional descriptive pilot study designed to provide preliminary data on prevalence, distribution and characteristics of near vision anomalies in a sample of high school-children in South Africa. Study participants comprised 65 Black children (30 males and 35 females), ages ranged between 13 and 19 years with a mean age and standard deviation of 17 ± 1.43 years. The visual functions evaluated and the techniques used included visual acuity (LogMAR acuity chart), refractive error (autorefractor and subjective refraction), heterophoria (von Graefe), near point of convergence (push-in-to-double), amplitude of accommodation (push-in-to-blur) accommodation facility (± 2 D flipper lenses), relative accommodation, accommodation response (monocular estimation method) and fusional vergences (step vergence with prism bars). Possible associations between symptoms and near vision anomalies were explored using a 20-point symptoms questionnaire. Results: Prevalence estimates were: Myopia 4.8%, hyperopia 1.6% and astigmatism 1.6%. For accommodative anomalies, 1.6% had accommodative insufficiency while 1.6% had accommodative infacility. For convergence anomalies, 3.2% had receded near point of convergence, 16% had low suspect convergence insufficiency, no participant had high suspect convergence insufficiency, 1.6% had definite convergence insufficiency and 3.2% had convergence excess. Female participants reported more symptoms than the males and the association between clinical measures and symptoms were not remarkable. Conclusion: Although the overall prevalence of near vision anomalies was low, convergence anomalies were found to be more prevalent than refractive and accommodative anomalies. Symptoms were not significantly associated with near vision anomalies. Overall, the pilot project reveals that it is feasible to conduct the study on a large scale with minor modifications. Identification and referrals for near vision anomalies are important steps towards diagnosis and treatment which will minimize discomfort with reading and subsequent poor performance which may be associated with such anomalies.

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Section: Introductionmentioning

confidence: 99%

“…Convergence insufficiency (CI) has been associated with attention deficit hyperactivity disorder (ADHD) [8][9][10][11] , anxiety, emotional and social problems [13][14] and lowered academic achievements [14][15] . In addition, NVAs are prevalent in populations of children with reading difficulties 12,16 and dyslexia 17 .…”

Section: Introductionmentioning

confidence: 99%

Near vision anomalies in Black high school children in Empangeni, South Africa: A pilot study

Wajuihian

Hansraj

2014

African Vision and Eye Health

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“…G*power software version 3.1.9.7 [ 13 ] was used to determine the minimum sample size using data from a similar study conducted in South Africa [ 12 ]. A calculated sample size of 22 children in each group was determined for a direct group comparison sufficient to achieve 80% statistical power with an attrition rate of 15% at a 95% confidence interval.…”

Section: Methodsmentioning

confidence: 99%

“…The prevalence of visual anomalies among dyslexic children has been assessed in some parts of the world, and its variation ranges from high to low [ 8 ]; in the USA, it was found to be very high, with a prevalence of 79% [ 11 ], and in Austria, the prevalence was estimated to be 33.9% [ 8 ], while there is also a report of a lower prevalence of less than 20% [ 11 ]. In Africa, there is only one study from South Africa conducted more than a decade ago, showing that accommodative infacility was prevalent among people with dyslexia [ 12 ]. There is a need to present recent data on dyslexia in Africa.…”

Section: Introductionmentioning

confidence: 99%

Age-Matched Comparative Analysis of Binocular Vision Anomalies among Children with Dyslexia in Northern Nigeria

Mukhtar,

Ezinne,

Mohamad Shahimin

et al. 2024

Pediatric Reports

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Background: Dyslexia, a neurodevelopmental disorder affecting reading skills, poses significant challenges to children’s academic performance and quality of life. Despite its rising prevalence and adverse effects, understanding of its relationship with vision anomalies remains limited, particularly in low-resource settings like Nigeria. This study aims to assess the prevalence of binocular vision anomalies (BVAs) among children with and without dyslexia in Kano, Nigeria. Methods: This is a hospital-based, cross-sectional, matched-paired, controlled study conducted at the Aminu Kano Teaching Hospital (AKTH) Eye Clinic in Northern Nigeria. The study included school children who visited the AKTH Eye Clinic from January 2018 to December 2022. Visual acuity tests, external eye examinations and accommodative, binocular vision and oculomotor skills tests were conducted. Descriptive statistics, independent t-tests, Mann–Whitney U tests and Fisher’s exact tests were conducted, with a significance level set at p < 0.05. Results: Forty-four children aged 12 ± 2 years participated. Children with dyslexia reported higher rates of visual symptoms than those without dyslexia, Blurring vision, visual distortion and eye strain were the most prevalent (p < 0.05) BV symptoms. Accommodative insufficiency), was the most common visual abnormality, and was significantly higher in children with dyslexia than those without dyslexia (45.5% vs. 18.2%). However, other visual anomalies showed no significant difference between groups. There was a high prevalence of binocular vision anomalies in both groups. Binocular test findings showed dyslexic children had significantly lower distance positive fusional vergence recovery values (p = 0.005). All cases of convergence insufficiency alone were found in the non-dyslexic group. Conclusions: The study found that children with dyslexia residing in Northern Nigeria demonstrated higher rates of visual symptoms, more accommodative insufficiency and lower distance positive fusional vergence recovery values compared to their non-dyslexic counterparts.

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“…Dyslexia is considered as one of the most common learning difficulties, with a high prevalence rate of around 80%, (. it affects nearly (5-10%) of school age students (Wajuihian & Naidoo, 2010;Huang, He, Li, Lin, Zhang & Wu, 2020). The International Dyslexia Association (2002) defined dyslexia as one of the specified learning difficulties, which are manifested in the form of a weakness in the considered the dual-route model as one of the most studied models, especially in the domain of reading and spelling.…”

Section: Introductionmentioning

confidence: 99%

Analyzing Reading Errors among Dyslexic Students According to the Dual-Route Model

Al-Natour¹,

Al-Mashayek²,

Alkhamra³

2022

INT J INSTRUCTION

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This study aimed at analyzing reading errors in the Arabic language among the dyslexic students based on the dual-route model for reading as well as determining the subtypes of dyslexia according to the reading errors manifested by the dyslexic students. The study sample consisted of eighty students divided equally between dyslexic and non-dyslexic students from the same age category. The dyslexic group were distributed into six students with surface dyslexia, four with phonological dyslexia, five with deep dyslexia and twenty five dyslexic students weren't identified in any of the above-mentioned types, accounting for (62.5%) of the total dyslexic sample. A battery of three domains was developed (reading errors, orthographic and phonological abilities and semantic abilities) with ten subdomains comprising of 200 items. A simple regression method and MANOVA were used for analysis. Results showed that students with surface dyslexia demonstrated visual errors in recognizing words, whereas the students with phonological dyslexia demonstrated phonological errors. However, the students with deep dyslexia mainly displayed semantic and phonological errors. Further implications were discussed.

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Visual factors and dyslexia: A research review

Cited by 4 publications

References 29 publications

Near vision anomalies in Black high school children in Empangeni, South Africa: A pilot study

Near vision anomalies in Black high school children in Empangeni, South Africa: A pilot study

Age-Matched Comparative Analysis of Binocular Vision Anomalies among Children with Dyslexia in Northern Nigeria

Analyzing Reading Errors among Dyslexic Students According to the Dual-Route Model

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