In the Beijing Eye Study, it was found that the major cause of vision manner, but a rebound effect (“catch-up”) occurs with higher doses (85). complete.pdf).
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The impact of myopia and high myopia: report of the Joint World Health OrganizationŒBrien Holden Vision Institute Global Scienti˜c Meeting on Myopia, University of New South Wales, Sydney, Australia, 16Œ18 March 2015 ISBN 978-92-4-151119-3© World Health Organization 2017 Some rights reserved. This work is available under the Creative Commons Attribution-NonCommercial-ShareAlike 3.0 IGO licence (CC BY-NC-SA 3.0 IGO; https://creativecommons.org/licenses/by-nc-sa/3.0/igo). Under the terms of this licence, you may copy, redistribute and adapt the work for non-commercial purposes, provided the work is appropriately cited, as indicated below. In any use of this work, there should be no suggestion that WHO endorses any speci˜c organization, products or services. The use of the WHO logo is not permitted. If you adapt the work, then you must license your work under the same or equivalent Creative Commons licence. If you create a translation of this work, you should add the following disclaimer along with the suggested citation: fiThis translation was not created by the World Health Organization (WHO). WHO is not responsible for the content or accuracy of this translation. The original English edition shall be the binding and authentic editionfl.Any mediation relating to disputes arising under the licence shall be conducted in accordance with the mediation rules of the World Intellectual Property Organization. Suggested citation. The impact of myopia and high myopia: report of the Joint World Health OrganizationŒBrien Holden Vision Institute Global Scienti˜c Meeting on Myopia, University of New South Wales, Sydney, Australia, 16Œ18 March 2015. Geneva: World Health Organization; 2017. Licence: CC BY-NC-SA 3.0 IGO. Cataloguing-in-Publication (CIP) data. CIP data are available at http://apps.who.int/iris. Sales, rights and licensing. To purchase WHO publications, see http://apps.who.int/bookorders. To submit requests for commercial use and queries on rights and licensing, see http://www.who.int/about/licensing. Third-party materials. If you wish to reuse material from this work that is attributed to a third party, such as tables, ˜gures or images, it is your responsibility to determine whether permission is needed for that reuse and to obtain permission from the copyright holder. The risk of claims resulting from infringement of any third-party-owned component in the work rests solely with the user. General disclaimers. The designations employed and the presentation of the material in this publication do not imply the expression of any opinion whatsoever on the part of WHO concerning the legal status of any country, territory, city or area or of its authorities, or concerning the delimitation of its frontiers or boundaries. Dotted and dashed lines on maps represent approximate border lines for which there may not yet be full agreement. The mention of speci˜c companies or of certain manufacturers™ products does not imply that they are endorsed or recommended by WHO in preference to others of a similar nature that are not mentioned. Errors and omissions excepted, the names of proprietary products are distinguished by initial capital letters. All reasonable precautions have been taken by WHO to verify the information contained in this publication. However, the published material is being distributed without warranty of any kind, either expressed or implied. The responsibility for the interpretation and use of the material lies with the reader. In no event shall WHO be liable for damages arising from its use. The named authors alone are responsible for the views expressed in this publication. Printed in Switzerland Designed by Inís Communication Œ www.iniscommunication.com
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Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v1. Executive summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.2 Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .11.3 Agreed conclusions and recommendations . . . . . . . . . . . . . . . . . 11.4 Speci˜c conclusions and recommendations . . . . . . . . . . . . . . . . . 22. Background and purpose of the consultation . . . . . . . . . . . . . . . . .43. Global prevalence of myopia . . . . . . . . . . . . . . . . . . . . . . . . . .54. Myopia as a cause of vision impairment and blindness. . . . . . . . . . . .75. Terminology and classi˜cation . . . . . . . . . . . . . . . . . . . . . . . . .85.1 Myopia, high myopia and pathologic myopia. . . . . . . . . . . . . . . . .85.2 Myopic macular degeneration . . . . . . . . . . . . . . . . . . . . . . . . 86. Impact of myopia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107. Evidence for causes of myopia . . . . . . . . . . . . . . . . . . . . . . . 117.1 Optical and environmental in˚uences . . . . . . . . . . . . . . . . . . . . 117.2 Genetics and parental history . . . . . . . . . . . . . . . . . . . . . . . . 128. Control of myopia . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138.1 Optical control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138.2 Time spent outdoors and behavioural in˚uences . . . . . . . . . . . . . . 158.3 Pharmacological and therapeutic control . . . . . . . . . . . . . . . . . . 15Contents
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iv9. Research . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179.1 Epidemiology of myopia . . . . . . . . . . . . . . . . . . . . . . . . . . 179.2 Myopigenesis, environmental, optical and therapeutic factors . . . . . . . 179.3 Risk factors and individual heterogeneity . . . . . . . . . . . . . . . . . . 189.4 High myopia, pathologic myopia and comorbid conditions. . . . . . . . . 189.5 Eye examinations in myopia . . . . . . . . . . . . . . . . . . . . . . . . 1810. Conclusions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20Annex˚1. Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25Annex˚2. Programme . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26Annex˚3. Regions de˜ned in the WHO Global Burden of Disease programme . . . . . . . . . . . . . . . . . . . . . . . . 29
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11. Executive summary 1.1 Introduction The prevalence of myopia and high myopia are increasing globally at an alarming rate, with signi˜cant increases in the risks for vision impairment from pathologic conditions associated with high myopia, including retinal damage, cataract and glaucoma. The impact of myopia is dif˜cult to determine, because there are no standard de˜nitions of myopia and high myopia, and recognition that myopia can lead to vision impairment is limited by the absence of a de˜ned category of myopic retinal disease that causes permanent vision impairment. A further impediment to progress in this area is insuf˜cient evidence of the ef˜cacy of various methods for controlling myopia. In view of concern about the current and future impact of myopia, the Minister of Health for Australia, the Right Honourable Mr Peter Dutton, contacted the Director-General of WHO, Dr Margaret Chan, to request the involvement of WHO in an international scienti˜c meeting on myopia to be held by the Brien Holden Vision Institute (BHVI). As a result, a three-day joint WHOŒBHVI meeting was convened on 16Œ18 March 2015 at the University of New South Wales in Sydney, Australia. 1.2 Summary Scienti˜c and clinical experts in myopia were invited from all six WHO regions (see Annex˛1). Keynote presentations, working groups and plenary sessions were held to review the evidence on the major issues in myopia. The results of these deliberations were reported to plenary for discussion, and agreement was reached on a series of statements, de˜nitions and priorities for research. 1.3 Agreed conclusions and recommendations The group agreed on de˜nitions of myopia and high myopia and on a category for and description of the pathologic consequences of myopia.The epidemiological surveys currently used to measure the status of vision (e.g. the WHO protocol and Rapid Assessment of Avoidable Blindness) do not allow the de˜nition of high myopia as a possible cause of vision impairment, partly because these surveys do not include a description of this condition or any measurement of refractive error. The group agreed that action should be taken to include myopia and high myopia among the attributable causes of vision impairment in the surveys currently used. Measures for the detection and management of myopia should be an integral part of plans for the provision of eye-care services. They should be part of general health care for vision impairment due to (i) the uncorrected refractive error associated with (the increased prevalence of) myopia; and (ii) the pathologic consequences of myopia.The term fimyopic macular degenerationfl (MMD) should be used clinically and in research to categorize the blinding retinal diseases associated with high myopia. Currently, a number of terms are used, including MMD, myopic maculopathy, myopic retinopathy and myopic choroidal neovascularization.
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2Epidemiological data are lacking on the prevalence of myopia, high myopia and vision impairment associated with high myopia in Africa, Central America, South America and Oceania. These areas should be priorities for future research. 1.4 Speci˜c conclusions and recommendations De˜nitions of myopia and high myopia The de˜nition of myopia is fia condition in which the spherical equivalent objective refractive error is ˝˛Œ0.50 diopter (Œ0.50˛D) in either eyefl. The de˜nition of high myopia is fia condition in which the spherical equivalent objective refractive error is ˝˛Œ5.00˛D in either eyefl. Clinical de˜nition of myopic macular degeneration The clinical de˜nition of myopic macular degeneration (MMD) is fia vision-threatening condition in people with myopia, usually high myopia, which comprises diffuse, patchy macular atrophy with or without lacquer cracks, choroidal neovascularization and Fuchs spotfl. It was agreed that the direct ophthalmoscope lens power wheel should be used in rapid assessments of avoidable blindness and other surveys to record the power at which the fundus is clearest, to ensure that possible cases of high myopia are recorded. Clinical and epidemiological research on myopia A cycloplegic agent should be used in clinical or epidemiological studies of children under the age of 18˛years.In surveys and studies, the continuous distribution of age and refractive errors should be reported for people up to the age of 25˛years. The ocular history of individuals should include interventions such as refractive surgery and other procedures to reduce refractive error, but not necessarily the consequences of axial eye elongation.The use of cycloplegic investigation and its inclusion in survey protocols for both young adults and adults should be investigated further. Attributing vision loss to high myopia or MMD in blindness surveys (rapid assessment of avoidable blindness, WHO survey protocol and others) It was agreed that the term fimyopic macular degenerationfl (MMD) should be used to de˜ne the retinal condition that causes vision impairment in myopia, because it is clearly de˜ned and easily categorized for rapid assessment of avoidable blindness, in the WHO survey protocol and others.De˜nition of MMD for the purposes of epidemiological surveys The de˜nition of MMD for the purposes of epidemiological surveys (e.g. rapid assessment of avoidable blindness, WHO survey protocol) with limited resources and in remote settings was agreed to be: fivision impairment and visual acuity that are not improved by pinhole and cannot be attributed to other causes, and direct ophthalmoscopy records a supplementary lens: ˝˛Œ5.00˛D and changes such as fipatchy atrophyfl in the retina, or ˝˛Œ10.00˛Dfl.
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3Myopia correction Access to correction for myopia is essential to avoid vision impairment. All people with myopia should have access to appropriate, accurate refractive correction. Myopia control Although there is a widely held clinical view that undercorrection of myopia is bene˜cial in preventing its progression, the available evidence does not support this idea. Recent reports show that undercorrection is associated with a higher rate of progression of myopia. Some initial published evidence indicates that time spent outdoors can delay the onset and perhaps reduce the progression of myopia, although more research is required, as it is also potentially a risk factor. If the evidence is proved correct, it will add bene˜cial eye care to the list of other health-promoting outdoor activities (e.g. reduction of childhood obesity through exercise, exposure to sunlight for vitamin˛D production, games for socialization). There is published evidence that excessive near work increases the risk of myopia. There is published evidence that multifocal spectacles can slightly reduce the rate of progress of myopia; executive bifocal lenses are associated with substantially larger reductions. Specially designed contact lenses that reduce peripheral hyperopia and/or create signi˜cant myopic defocus can slow the progress of myopia. It is important that contact lenses are appropriately cared for in order to avoid adverse effects. Orthokeratology can slow the progress of myopia, but overnight wear of contact lenses is associated with risks.Low-dose atropine has been shown to be effective in reducing the progression of myopia but not in slowing the rate of increase of axial length. A dose of 0.01% has few side-effects, but more research is required to determine the optimal regimen. Other agents have been suggested for the control of myopia, such as 7-methylxanthine; however, larger clinical trials are needed to establish their safety and ef˜cacy. Pathological consequences of myopia (pathologic myopia) High myopia can cause serious, sight-threatening retinal damage. Hence, the following recommendations were agreed for the care and management of pathologic myopia. Patients with complications from pathologic myopia should have access to a full range of eye-care services. Myopic choroidal neovascularization is one of the consequences of high myopia that causes vision impairment; agents against vascular endothelial growth factor may be bene˜cial in the treatment of this condition, but the long-term prognosis for vision is unknown. Myopia increases the risk of glaucoma; glaucomatous optic neuropathy should be investigated in patients with high myopia.Myopia increases the risk of retinal detachment and cataract; a fundus and anterior segment examination is essential for people with high myopia.People with vision impairment that cannot be corrected to a level of vision that they ˜nd acceptable should have access to comprehensive eye-care services, including vision rehabilitation and appropriate devices and surgery if necessary.
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