Prevalence and Causes of Low Vision and Blindness in a Rural Chinese Adult Population

Liang, Yuan Bo; Friedman, David S.; Wong, Tien Yin; Zhan, Si Yan; Sun, Lan; Wang, Jie Jin; Duan, Xiaohui; Xiao, Yang; Wang, Feng Hua; Zhou, Qiang; Wang, Ning Li

doi:10.1016/j.ophtha.2008.05.030

Cited by 202 publications

(150 citation statements)

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“…This is also lower than in studies conducted in neighbouring countries and the estimate of 3.4% for the South East Asian region (Resnikoff et al, 2004;Dandona et al, 2001;Thulisiraj et al, 2003; p-value 0.008 < 0.001 < 0.001 < 0.001 Dunzhu et al, 2003). However, there are several studies in Asia that have also reported a low prevalence of blindness ( Liang et al, 2008;Wong et al, 2008, Zainal et al, 2010, Michon et al, 2002Iwase et al (2006). After best correction the prevalence of blindness was 0.43% in our study.…”

Section: Thapa Ss Et Al Results Of the Bhaktapur Glaucomamentioning

confidence: 99%

Results of the Bhaktapur Glaucoma Study, Nepal

et al. 2013

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I nt r oduction: The Bhaktapur Glaucoma Study is a population-based, cross-sectional and longitudinal study undertaken in one of the districts of Nepal. Objectives: To determine the prevalence of glaucoma in Bhaktapur district, Nepal. Materials and methods: Thirty clusters were randomly selected and a door-to-door census was conducted to identify citizens 40 years of age and older. Four thousand eight hundred individuals fulfilling the eligibility criteria were referred to the base hospital in Kathmandu for a detailed clinical examination. The diagnosis of glaucoma was based upon criteria described by the International Society for Geographic and Epidemiological Ophthalmology (ISGEO). Results: Complete data was available on 3991 subjects (response rate 83.15 %). The mean IOP was 13.3 mm Hg (97.5 th and 99.5 th percentiles, 18 and 20 mm Hg, respectively) and mean VCDR 0.26 (97.5 th and 99.5 th percentiles, 0.6 and 0.8 mm Hg, respectively). Seventy-five subjects had glaucoma, an age-sex-standardized prevalence of 1.80 (95 % confidence interval (CI), 1.68 -1.92). The age-and sex-standardized prevalence of POAG was 1.24 % (CI, 1.14 -1.34), PACG 0.39 % (CI, 0.34 -0.45) and secondary glaucoma 0.15 % (CI, 0.07-0.36). The prevalence of glaucoma increased with increase in age and there was no significant difference in gender. Nine eyes were blind and two subjects bilaterally blind from glaucoma. Conclusion: The overall prevalence of glaucoma was 1.9 %. POAG was the most common form of glaucoma. Visual morbidity from PACG, however, was higher. A large majority of the subjects with POAG had not been previously diagnosed and had intraocular pressure within the normal range.

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Section: Thapa Ss Et Al Results Of the Bhaktapur Glaucomamentioning

confidence: 99%

Results of the Bhaktapur Glaucoma Study, Nepal

et al. 2013

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“…5,6 Despite intensive research in recent decades, the etiology of myopia remains elusive. Although on-axis refraction (central refractive error) is the major determinant of central visual acuity, there is increasing evidence suggesting that peripheral defocus also plays an important role in the development of myopia, 7-12 although one study has reported contradictory results.…”

Section: Purposementioning

confidence: 99%

Heritability of Peripheral Refraction in Chinese Children and Adolescents: The Guangzhou Twin Eye Study

Ding

Lin

Huang

et al. 2012

Invest. Ophthalmol. Vis. Sci.

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PURPOSE.To estimate the heritability of peripheral refraction in Chinese children and adolescents. METHODS. The authors examined 72 monozygotic (MZ) twins and 48 dizygotic (DZ) twins aged 8 to 20 years from a population-based twin registry. Temporal and nasal peripheral refraction, each 40°from the visual axis, and axial refraction were measured using an autorefractor. Relative peripheral refractive error (RPRE) was defined as the peripheral refraction minus the axial refraction. Heritability was assessed by structural equation modeling after adjustment for age and sex. 1 Longitudinal and crosssectional epidemiologic studies have suggested that the prevalence of myopia exceeds 70% among teenagers living in urban areas in East Asia.2-4 In recent population-based studies among adult Chinese living in urban and rural settings, myopic retinopathy has been the second-leading cause of blindness after cataract. 5,6 Despite intensive research in recent decades, the etiology of myopia remains elusive. Although on-axis refraction (central refractive error) is the major determinant of central visual acuity, there is increasing evidence suggesting that peripheral defocus also plays an important role in the development of myopia, 7-12 although one study has reported contradictory results. 13 In keeping with this notion, previous studies have shown that subjects with relative hyperopic peripheral refraction are more likely to have a prolate posterior eye shape. 14 -16 By contrast, those with relative myopic peripheral refraction are more likely to have an oblate posterior eye shape. 14 -16 Interestingly, there appears to be ethnic variation in the distribution of peripheral refraction, with East Asians having a greater degree of relative peripheral hyperopia (more prolate ocular shape) than do persons of European descent with similar central refractive power. [17][18][19] It remains unclear whether this ethnic difference is attributable to inherited genetic susceptibilities or socioenvironmental differences. It is therefore important to understand whether peripheral refraction is genetically determined. Such information may shed light on the mechanisms underlying the development of myopia.Twin studies offer a unique opportunity to estimate the relative contribution of genetic and environmental effects to the development of complex traits and diseases. 20 In classic twin studies, it is assumed that monozygotic (MZ) twins share 100% of their genes, whereas dizygotic (DZ) twins share, on average, 50%. The heritability of a specific phenotype can be estimated by comparing the phenotypic concordance within MZ and DZ twin pairs. The purpose of this study was to estimate the distribution and heritability of peripheral refraction in young twins. SUBJECTS, MATERIALS, AND METHODS SubjectsSubjects were recruited from participants in the Guangzhou Twin Study, an ongoing prospective cohort study of 9709 twin pairs that began in 2006.21 Children older than 8 years of age who visited the Zhongshan Ophthalmic Center between

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“…[1][2][3][4][5] It is characterized by excessive axial elongation of the eye, scleral thinning, posterior staphyloma, chorioretinal atrophy, and choroidal neovascularization. 6 The prevalence of MMD in East Asia is estimated to be 1.7% to 3.1%, 7,8 but because MMD also affects young and middle-aged working adults, 9,10 it carries a significant socioeconomic burden.…”

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confidence: 99%

Is Choroidal or Scleral Thickness Related to Myopic Macular Degeneration?

Wong

Phua

Lee

et al. 2017

Invest. Ophthalmol. Vis. Sci.

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Citation: Wong CW, Phua V, Lee SY, Wong TY, Cheung CMG. Is choroidal or scleral thickness related to myopic macular degeneration? Invest Ophthalmol Vis Sci. 2017;58:907-913. DOI:10.1167/iovs.16-20742 PURPOSE. The relative contribution of mechanical and vascular factors to the pathogenesis of myopic macular degeneration (MMD) is unclear. To address this gap, we examined the association of choroidal thickness (CT) and scleral thickness (ST) with MMD.METHODS. Prospective, clinic-based case series of 62 eyes of 41 patients with high myopia ( À6 diopters or axial length ‡26.5 mm). Swept-source optical coherence tomography (SSOCT) was performed to measure subfoveal CT and ST. Myopic macular degeneration was graded from fundus photographs according to the International Meta-Analysis for Pathologic Myopia (META-PM) classification. Presence of MMD was defined as META-PM category ‡ 2 and severe MMD was defined as category ‡ 3.RESULTS. The distribution of MMD severity was 15 (24.2%) in category 1, 28 (45.2%) in category 2, 10 (16.1%) in category 3, and 9 (14.5%) in category 4. Correlation of MMD severity was strong for subfoveal CT (r ¼ À0.70, P < 0.001) but weak for subfoveal ST (r ¼ À0.31, P ¼ 0.01). Subfoveal CT, but not ST, was independently associated with presence of MMD (age and gender adjusted odds ratio [OR] per 10 lm decrease in CT 1.41, P ¼ 0.002), and subfoveal CT, but not subfoveal ST, was significantly thinner in eyes with severe MMD ( ‡ category 3) than in eyes with mild MMD (CT: 31.5 6 40.5 lm versus 82.0 6 57.1 lm, P < 0.001; ST: 261.6 6 78.5 lm versus 297.0 6 73.8 lm, P ¼ 0.09). CONCLUSIONS.We demonstrated significant thinning of the choroid with increasing MMD severity. In contrast, ST was weakly correlated with MMD. These data suggest progressive loss of choroid may be important in the pathogenesis of MMD.

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Prevalence and Causes of Low Vision and Blindness in a Rural Chinese Adult Population

Cited by 202 publications

References 21 publications

Results of the Bhaktapur Glaucoma Study, Nepal

Results of the Bhaktapur Glaucoma Study, Nepal

Heritability of Peripheral Refraction in Chinese Children and Adolescents: The Guangzhou Twin Eye Study

Is Choroidal or Scleral Thickness Related to Myopic Macular Degeneration?

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