Association Of High Myopia Research Articles

Myopia prevalence in school-aged children in Garki District of Abuja, Nigeria

Background: Prevalence of myopia is increasing globally, hence it poses a significant public health risk due to the association of high myopia with debilitating eye disorders.Aim: The aim of this study was to determine the prevalence of myopia in school children.Setting: The study was conducted in primary and secondary schools in Garki district, Abuja, Nigeria.Methods: A cross-sectional, multistage, random sampling involving 1028 school children (aged 5–14 years), comprising 484 boys (47.1%) and 544 girls (52.9%), was conducted. Examination performed included visual acuities, pen torch and ophthalmoscopy examination of the anterior and posterior segments, retinoscopy under cycloplegia and subjective refraction.Results: The prevalence of myopia (−0.50 dioptre [D] or more) in this study was 3.5%. Approximately 3.4% of the children had mild myopia (−0.50 to −3.00 D), 0.1% had moderate myopia (−3.25 D to −6.00 D) and none had high myopia. Myopia ranged from −0.50 D to −4.25 D. The mean spherical equivalent for myopia (right eye) was −1.11 D. The prevalence of hyperopia, astigmatism and amblyopia was 5.8%, 1.9% and 0.7%, respectively. Overall, the prevalence of refractive error was 11.2%.Conclusion: The prevalence of myopia is relatively low in a sample of school children in Garki district of Abuja, Nigeria. However, the majority of myopic children in this study without spectacles (88.9%) are a cause for concern, which could reflect the low usage of refractive error services among school children in the district.

Association of high myopia with peripapillary retinal nerve fiber layer in patients with hypertension.

PurposeTo identify the impacts of hypertension (HTN), high myopia, and the combination thereof on peripapillary retinal nerve fiber layer (pRNFL) thickness.MethodsAll subjects were divided into four groups: control (group 1); patients with HTN without high myopia (group 2); patients with high myopia without HTN (group 3); and patients with both HTN and high myopia (group 4). The pRNFL thicknesses were compared using a one-way analysis of variance. Univariate and multivariate linear regression analyses were used to identify factors affecting pRNFL thickness in subjects with and without HTN.ResultsThe mean pRNFL thicknesses were 93.9±8.8, 88.7±6.8, 86.4±8.1, and 82.5±9.6 μm in group 1, 2, 3, and 4, respectively, and differed significantly (P<0.001). On multivariate linear regression analyses, age (β = -0.181, P = 0.044), axial length (β = -1.491, P<0.001), and HTN (β = -4.876, P = 0.044) significantly affected pRNFL thickness. Additionally, age and axial length affected the pRNFL thickness in subjects with HTN (age, β = -0.254, P = 0.020; axial length, β = -1.608, P<0.001) much more than in subjects without HTN (age, β = -0.028, P = 0.712; axial length, β = -1.324, P<0.001).ConclusionsHigh myopia and HTN affected pRNFL reduction and a combination of the 2 diseases exacerbated pRNFL damage. This could be a confounding factor in interpreting pRNFL thickness in patients with ophthalmic diseases affecting the pRNFL thickness when combined with the 2 diseases.

Association of High Myopia with Crystallin Beta A4 (CRYBA4) Gene Polymorphisms in the Linkage-Identified MYP6 Locus

BackgroundMyopia is the most common ocular disorder worldwide and imposes tremendous burden on the society. It is a complex disease. The MYP6 locus at 22 q12 is of particular interest because many studies have detected linkage signals at this interval. The MYP6 locus is likely to contain susceptibility gene(s) for myopia, but none has yet been identified.Methodology/Principal FindingsTwo independent subject groups of southern Chinese in Hong Kong participated in the study an initial study using a discovery sample set of 342 cases and 342 controls, and a follow-up study using a replication sample set of 316 cases and 313 controls. Cases with high myopia were defined by spherical equivalent ≤ -8 dioptres and emmetropic controls by spherical equivalent within ±1.00 dioptre for both eyes. Manual candidate gene selection from the MYP6 locus was supported by objective in silico prioritization. DNA samples of discovery sample set were genotyped for 178 tagging single nucleotide polymorphisms (SNPs) from 26 genes. For replication, 25 SNPs (tagging or located at predicted transcription factor or microRNA binding sites) from 4 genes were subsequently examined using the replication sample set. Fisher P value was calculated for all SNPs and overall association results were summarized by meta-analysis. Based on initial and replication studies, rs2009066 located in the crystallin beta A4 (CRYBA4) gene was identified to be the most significantly associated with high myopia (initial study: P = 0.02; replication study: P = 1.88e-4; meta-analysis: P = 1.54e-5) among all the SNPs tested. The association result survived correction for multiple comparisons. Under the allelic genetic model for the combined sample set, the odds ratio of the minor allele G was 1.41 (95% confidence intervals, 1.21-1.64).Conclusions/SignificanceA novel susceptibility gene (CRYBA4) was discovered for high myopia. Our study also signified the potential importance of appropriate gene prioritization in candidate selection.

High Myopia in Pallister Mosaic Syndrome

Pallister mosaic syndrome, a genetic disorder, has various systemic and ocular manifestations. We report the first association of high myopia with Pallister mosaic syndrome.

Association of diabetes mellitus and high myopia in primary open angle glaucoma

Background: Primary open angle glaucoma (POAG), a chronic, slowly progressive, optic neuropathy, is insidious in onset and painless, until it has caused a significant loss of vision and visual field. Diabetes mellitus and high myopia are the major risk factor of POAG. Objectives: To determine correlation of diabetes mellitus and high myopia in POAG and to estimate the duration of onset of POAG from the diagnosis of diabetes mellitus and high myopia. Method: This retrospective and cross sectional study was conducted in Prabhudesai eye clinic, Pune, India. All the patients diagnosed as POAG from 1st September 2008 to 1st March 2009 AD were included in this study. Association of high myopia with diabetes mellitus was determined by SPSS 13 software. The average duration of onset of POAG after the diagnosis of diabetes mellitus and high myopia was calculated. Results: There were 63.3% (38) male and 36.7% (22) female out of 60 patients of POAG with mean age 54.4±15.4 years. Among them, 27 (45.0%) patients had diabetes mellitus or high myopia. Onset of POAG was found to occur after 11.1±8.3 years of the diagnosis of diabetes and 10.6±3.2 years after the diagnosis of high myopia. Conclusion: The incidence of diabetes mellitus and high myopia was high and significantly associated in primary open angle glaucoma. POAG was detected soon after the onset of diabetes mellitus and high myopia. DOI: http://dx.doi.org/10.3126/hren.v10i1.6005 HREN 2012; 10(1): 35-39