Myopia and high myopia estimates from 2000 to 2050 suggest significant increases in prevalences globally, with implications for planning services, including managing and preventing myopia-related ocular complications and vision loss among almost 1 billion people with high myopia.

PurposeWe provide a standardized set of terminology, definitions, and thresholds of myopia and its main ocular complications.MethodsCritical review of current terminology and choice of myopia thresholds was done to ensure that the proposed standards are appropriate for clinical research purposes, relevant to the underlying biology of myopia, acceptable to researchers in the field, and useful for developing health policy.ResultsWe recommend that the many descriptive terms of myopia be consolidated into the following descriptive categories: myopia, secondary myopia, axial myopia, and refractive myopia. To provide a framework for research into myopia prevention, the condition of “pre-myopia” is defined. As a quantitative trait, we recommend that myopia be divided into myopia (i.e., all myopia), low myopia, and high myopia. The current consensus threshold value for myopia is a spherical equivalent refractive error ≤ −0.50 diopters (D), but this carries significant risks of classification bias. The current consensus threshold value for high myopia is a spherical equivalent refractive error ≤ −6.00 D. “Pathologic myopia” is proposed as the categorical term for the adverse, structural complications of myopia. A clinical classification is proposed to encompass the scope of such structural complications.ConclusionsStandardized definitions and consistent choice of thresholds are essential elements of evidence-based medicine. It is hoped that these proposals, or derivations from them, will facilitate rigorous, evidence-based approaches to the study and management of myopia.

Purpose: We estimated the potential global economic productivity loss resulting from vision impairment (VI) and blindness as a result of uncorrected myopia and myopic macular degeneration (MMD) in 2015. Clinical Relevance: Understanding the economic burden of VI associated with myopia is critical to addressing myopia as an increasingly prevalent public health problem. Methods: We estimated the number of people with myopia and MMD corresponding to critical visual acuity thresholds. Spectacle correction coverage was analyzed against country-level variables from the year of data collection; variation in spectacle correction was described best by a model based on a human development index, with adjustments for urbanization and age. Spectacle correction and myopia data were combined to estimate the number of people with each level of VI resulting from uncorrected myopia. We then applied disability weights, labor force participation rates, employment rates, and gross domestic product per capita to estimate the potential productivity lost among individuals with each level and type of VI resulting from myopia in 2015 in United States dollars (US$). An estimate of care-associated productivity loss also was included. Results: People with myopia are less likely to have adequate optical correction if they are older and live in a rural area of a less developed country. The global potential productivity loss associated with the burden of VI in

PurposeWe used systematic review and meta-analysis to identify and assimilate evidence quantifying blindness and visual impairment (VI) associated with myopic macular degeneration (MMD), then derived models to predict global patterns. The models were used to estimate the global prevalence of blindness and VI associated with MMD from 2000 to 2050.MethodsThe systematic review identified 17 papers with prevalence data for MMD VI fitting our inclusion criteria. Data from six papers with age-specific data were scaled to relative age-dependent risk and meta-analysed at VI and blindness levels. We analysed variance in all MMD VI and blindness data as a proportion of high myopia against variables from the place and year of data collection, with a model based on health expenditure providing the best correlation. We used this model to estimate the prevalence and number of people with MMD VI in each country in each decade.ResultsWe included data from 17 studies comprising 137 514 participants. We estimated 10.0 million people had VI from MMD in 2015 (prevalence 0.13%, 95% CI 5.5 to 23.7 million, 0.07% to 0.34%), 3.3 million of whom were blind (0.04%, 1.8 to 7.8 million, 0.03% to 0.10%). We estimate that by 2050, without changing current interventions, VI from MMD will grow to 55.7 million people (0.57%, 29.0 to 119.7 million, 0.33% to 1.11%), 18.5 million of whom will be blind (0.19%, 9.6 to 39.7 million, 0.11% to 0.37%).ConclusionThe burden of MMD blindness and VI will rise significantly without efforts to reduce the development and progression of myopia and improve the management of MMD.

The prevalence of myopia has markedly increased in East and Southeast Asia, and pathologic consequences of myopia, including myopic maculopathy and high myopia-associated optic neuropathy, are now some of the most common causes of irreversible blindness. Hence, strategies are warranted to reduce the prevalence of myopia and the progression to high myopia because this is the main modifiable risk factor for pathologic myopia. On the basis of published population-based and interventional studies, an important strategy to reduce the development of myopia is encouraging schoolchildren to spend more time outdoors. As compared with other measures, spending more time outdoors is the safest strategy and aligns with other existing health initiatives, such as obesity prevention, by promoting a healthier lifestyle for children and adolescents. Useful clinical measures to reduce or slow the progression of myopia include the daily application of low-dose atropine eye drops, in concentrations ranging between 0.01% and 0.05%, despite the side effects of a slightly reduced amplitude of accommodation, slight mydriasis, and risk of an allergic reaction; multifocal spectacle design; contact lenses that have power profiles that produce peripheral myopic defocus; and orthokeratology using corneal gas-permeable contact lenses that are designed to flatten the central cornea, leading to midperipheral steeping and peripheral myopic defocus, during overnight wear to eliminate daytime myopia. The risk-to-benefit ratio needs to be weighed up for the individual on the basis of their age, health, and lifestyle. The measures listed above are not mutually exclusive and are beginning to be examined in combination.

Myopia is the most frequent cause of distance impairment in the world and is creating an alarming global epidemic with deleterious ramifications for the quality of life and economic health of individuals and nations as a whole. In addition to being immediately disadvantageous, myopia increases the risk of serious disorders such as myopic macular degeneration, retinal detachment, glaucoma, and cataract and is a leading cause of visual impairment and blindness across many countries. The reduction in age of onset of myopia is of great concern since the earlier the onset, the more myopic the individual will become, with all the attendant increased risks of accompanying debilitating eye conditions. The economic burden is great; both in consequences of uncorrected refractive error and also in the provision of devices for correcting visual acuity. Earlier onset of myopia increases the lifetime economic burden related to loss of productivity and independence, leading to a reduced quality of life. Recent data suggest addressing accommodation per se has little direct amelioration of myopia progression. Pharmacological interventions that effect changes in the sclera show promising efficacy, whereas optical interventions based on a myopic shift in the retinal image are proving to effect up to 55% reduction in the rate of progression of myopia. Early contact lens and spectacle interventions that reduce the rate of progression of myopia are able to significantly reduce the burden of myopia. These nonpharmacological interventions show profound promise in reducing the overall associated morbidity of myopia.

With the growing prevalence of myopia, already at epidemic levels in some countries, there is an urgent need for new management approaches. However, with the increasing number of research publications on the topic of myopia control, there is also a clear necessity for agreement and guidance on key issues, including on how myopia should be defined and how interventions, validated by well-conducted clinical trials, should be appropriately and ethically applied. The International Myopia Institute (IMI) reports the critical review and synthesis of the research evidence to date, from animal models, genetics, clinical studies, and randomized controlled trials, by more than 85 multidisciplinary experts in the field, as the basis for the recommendations contained therein. As background to the need for myopia control, the risk factors for myopia onset and progression are reviewed. The seven generated reports are summarized: (1) Defining and Classifying Myopia, (2) Experimental Models of Emmetropization and Myopia, (3) Myopia Genetics, (4) Interventions for Myopia Onset and Progression, (5) Clinical Myopia Control Trials and Instrumentation, (6) Industry Guidelines and Ethical Considerations for Myopia Control, and (7) Clinical Myopia Management Guidelines.

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