Childhood exposure to constricted living space: a possible environmental threat for myopia development

Choi, Kai Yip; Yu, Wing Yan; Lam, Christie Hang-I; Li, Zhe Chuang; Chin, Man Pan; Lakshmanan, Yamunadevi; Wong, Francisca Siu Yin; Wai, Chi; Lee, Paul H.; Chan, Ho Lung Henry

doi:10.1111/opo.12397

Cited by 47 publications

(48 citation statements)

References 31 publications

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“…One limitation of our study is that the numbers of children with different refractive errors (low and high myopia, high astigmatism) were not large enough to conduct separate analyses on the association between ocular HOA and axial elongation in different refractive error groups treated with ortho-k. As a result, all subjects were pooled together to provide a general understanding of the association between HOA and axial eye growth with ortho-k treatment. Because emmetropization is a complex, multifactorial process, other possible confounding factors such as pupil size, 49,50 parental myopia, 56 outdoor activities, 57 and living conditions 58 should also be evaluated in future studies (or controlled for with statistical modeling).…”

Section: Discussionmentioning

confidence: 99%

Higher-Order Aberrations and Axial Elongation in Myopic Children Treated With Orthokeratology

Lau

Vincent

Cheung

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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Citation: Lau JK, Vincent SJ, Cheung S-W, Cho P. Higher-order aberrations and axial elongation in myopic children treated with orthokeratology. Invest Ophthalmol Vis Sci. 2020;61(2):22. https://doi.org/10.1167/iovs. 61.2.22 PURPOSE. This retrospective longitudinal study aimed to examine the relationship between ocular higher-order aberrations (HOA) and axial eye growth in young myopic children undergoing orthokeratology (ortho-k) treatment. METHODS.Axial length and ocular HOA, measured under cycloplegia annually over a 2year period from the right eyes of myopic children, who previously completed ortho-k clinical trials, were retrieved. Linear mixed model analyses were applied to determine the association between ocular HOA, other known confounding variables (age, sex, and refractive error), and axial eye growth. RESULTS.Data from 103 subjects were analyzed. The root-mean square (RMS) values of total ocular HOA (third to sixth orders combined), spherical (Z 0 4 and Z 0 6 combined), and comatic (Z −1 3 , Z 1 3 , Z −1 5 , and Z 1 5 combined) aberrations increased by approximately 3, 9, and 2 times, respectively, after 2 years of ortho-k treatment. After adjusting for age, sex, and refractive error, higher RMS values of total HOA and spherical aberrations were associated with both longer axial length and slower axial elongation (all P < 0.01). For individual Zernike term coefficients, a higher level of positive spherical aberration (Z 0 4 ) was also associated with longer axial length and slower axial elongation (both P < 0.01), after adjusting for baseline HOA. CONCLUSIONS.Ortho-k for myopia control significantly increases the Zernike coefficients and therefore the RMS values for a range of total ocular HOA terms or metrics in children. These findings suggest the potential role of HOA, particularly spherical aberration, as the possible mechanism of slowing axial elongation in ortho-k treatment.

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Section: Discussionmentioning

confidence: 99%

Higher-Order Aberrations and Axial Elongation in Myopic Children Treated With Orthokeratology

Lau

Vincent

Cheung

et al. 2020

Invest. Ophthalmol. Vis. Sci.

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“…Higher population density seems to be associated with myopia risk, independent of time spent outdoors and other environmental factors [68]. High population density and small home size was also associated with longer axial length and refractive error in children in Hong Kong and Beijing [48,69]. The Beijing study reported other risks factors that are associated with myopia, such as urban region of habitation [69].…”

Section: Population Densitymentioning

confidence: 92%

“…China [14] Hong Kong [48] Indonesia [34] Rural environment Saudi Arabia (only in girls) [21] Private schooling and watching TV over 2 h daily and playing mobile/video games India [17] Low sleeping hours China [32] Lower vitamin D levels, less participation in sports and foreign descent Netherlands [23] Westernized dietary habits Japan [46] randomized clinical trial by He et al, a 40-min class of outdoor activities on each school day for 3 years resulted in a reduced incidence of myopia from 39.5 to 30.4% [1]. A recent RCT showed that outdoor activities can inhibit progression in myopic children aged 6 to 7 years old by 30% in 1 year [2].…”

Section: Risk Factormentioning

confidence: 99%

A review on the epidemiology of myopia in school children worldwide

Kanclerz²,

et al. 2020

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Background: Due to high prevalence myopia has gained importance in epidemiological studies. Children with early onset are at particular risk of complications associated with myopia, as progression over time might result in high myopia and myopic macular degeneration. Both genetic and environmental factors play a role in the increasing prevalence of myopia. The aim of this study is to review the current literature on epidemiology and risk factors for myopia in school children (aged 6-19 years) around the world. Main body: PubMed and Medline were searched for the following keywords: prevalence, incidence, myopia, refractive error, risk factors, children and visual impairment. English language articles published between were included in the study. Studies were critically reviewed for study methodology and robustness of data. Eighty studies were included in this literature review. Myopia prevalence remains higher in Asia (60%) compared with Europe (40%) using cycloplegic refraction examinations. Studies reporting on non-cycloplegic measurements show exceptionally high myopia prevalence rates in school children in East Asia (73%), and high rates in North America (42%). Low prevalence under 10% was described in African and South American children. In recent studies, risk factors for myopia in schoolchildren included low outdoor time and near work, dim light exposure, the use of LED lamps for homework, low sleeping hours, reading distance less than 25 cm and living in an urban environment. Conclusion: Low levels of outdoor activity and near work are well-established risk factors for myopia; this review provides evidence on additional environmental risk factors. New epidemiological studies should be carried out on implementation of public health strategies to tackle and avoid myopia. As the myopia prevalence rates in noncycloplegic studies are overestimated, we recommend considering only cycloplegic measurements.

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“…This suggests other aspects of the urban environment may potentially impact upon eye growth. Studies have also reported associations between housing type and myopia, with children living in smaller homes reported to have a significantly higher prevalence of myopia [253,254]. Although further research is required to establish the causative nature and mechanisms underlying these associations, it has been hypothesized that a constricted living space may result in an increased exposure to hyperopic blur, thus promoting myopia.…”

Section: Urbanizationmentioning

confidence: 99%

Understanding Myopia: Pathogenesis and Mechanisms

2019

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• Visual environment (or the quality of the retinal image) modulates the refractive development of the eye. • Ocular response to form-deprivation and lens induced defocus is evident across a wide range of animal species, including humans. • The visual system appears to be more sensitive to myopic than hyperopic defocus. • Evidence suggests that greater time spent outdoors is protective against development and progression of myopia in children.

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Childhood exposure to constricted living space: a possible environmental threat for myopia development

Cited by 47 publications

References 31 publications

Higher-Order Aberrations and Axial Elongation in Myopic Children Treated With Orthokeratology

Higher-Order Aberrations and Axial Elongation in Myopic Children Treated With Orthokeratology

A review on the epidemiology of myopia in school children worldwide

Understanding Myopia: Pathogenesis and Mechanisms

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