October 1, 2024
By Dwight Akerman, OD, MBA, FAAO, FBCLA, FIACLE
Photo Credit: Getty Images
The National Academies of Sciences, Engineering, and Medicine recently published a new 374-page consensus study entitled Myopia: Causes, Prevention, and Treatment of an Increasingly Common Disease.
The National Academies appointed the Committee on Focus on Myopia: Pathogenesis and Rising Incidence to identify and assess the current mechanistic understanding of myopia pathogenesis and the causes of myopia’s increased prevalence, to identify knowledge gaps and barriers to progress and to develop a research agenda aimed at better understanding the biological and environmental factors that could explain its increasing incidence. Experts in vision science, visual neuroscience, ophthalmology, optometry, physical and physiological optics, experimental methodology, human factors, genetics, computer sciences, psychology, population studies, and health care delivery, organization, and financing were considered for committee membership to address the committee charge from a holistic perspective.
The committee reviewed the literature on six topics: global data on myopia prevalence, technologies to assess and diagnose myopia, environmental and genetic contributions to myopia onset and progression, the mechanistic causes of myopia pathogenesis, treatment optics for myopia, and barriers to vision care for children with myopia. The major conclusions and recommendations are summarized below.
UNDERSTANDING MYOPIA AND ITS PREVALENCE
Conclusions: The prevalence of myopia appears to be increasing worldwide, including in the United States. Most research comes from international studies, with limited evidence available in the United States due to a lack of standardized definitions of myopia, irregular and inconsistent screening practices locally to nationally, and the use of varied assessment techniques.
Recommendations: The Centers for Disease Control and Prevention and state health departments should collect consistent, harmonized data on the prevalence of myopia in the United States, prioritizing longitudinal surveillance on refractive error prevalence in children using standardized procedures. Furthermore, the Centers for Disease Control and Prevention should coordinate with the World Health Organization to create consistent, harmonized definitions and monitoring methods that would benefit the global community.
ASSESSMENT AND DIAGNOSTIC TECHNOLOGIES
Conclusions: There is no consensus as to the mandatory assessment and diagnostic components of a clinical examination of the myopia patient. Diagnostic technologies sensitive to newly understood biomarkers are under development that may improve diagnostics, management, and understanding of myopia.
Recommendations: To obtain a consistent retinoscopy/refractive reading, ophthalmologists and optometrists should use cycloplegic eye drops in children. Researchers and developers of assessment and diagnostic technologies should design assessments and tests to understand better the myopic eye, its development, and its environment (the visual diet). This could lead to better methods to identify myopic eyes and those at risk for myopia.
ONSET AND PROGRESSION OF MYOPIA
Conclusions: Environmental factors, particularly the protective effect of outdoor time during daylight, appear to play a significant role in myopia development, suggesting a larger influence than genetics. Significant gaps in knowledge exist regarding the impact of electronic devices on myopic eye growth of “near work,” both with and without electronic devices. While evidence suggests other aspects of the visual diet (such as spectra and contrast from different light sources) also affect eye growth, important details are lacking.
Recommendations: The Centers for Disease Control should produce evidence-based guidelines supported by Departments of Education and health care providers, promoting more time outdoors (at least one to two hours per day) for children. The National Institutes of Health and other funding agencies should solicit and fund research to investigate novel questions about the genetic and environmental mechanisms of myopia.
MYOPIA PATHOGENESIS: FROM RETINAL IMAGE TO SCLERAL GROWTH
Conclusions: Retinal images regulate eye growth, with the entire retina (not just the fovea) playing a critical role. The retinal network, which encodes light intensity, provides a mechanistic link between reduced time outdoors and increased incidence of myopia that is supported by multiple lines of evidence. The specific retinal image properties and mechanisms encoding the retino-scleral signaling cascade for homeostasis of eye growth are currently unknown. Animal models have provided important insights into potentially conserved processes controlling postnatal eye growth, such as visually driven signaling events in the retina, retinal pigment epithelium, and choroid that regulate the rapid remodeling of the scleral extracellular matrix, thereby changing eye size and refraction.
Recommendations: Funding agencies, including the National Institutes of Health, the National Science Foundation, the Department of Defense, and private foundations, as well as industry, should seek to fund proposals across disciplines for both human and animal studies to investigate the mechanisms of emmetropization and myopia, including candidates for retino-scleral signaling, retinal neurons that detect the sign of defocus, the role of the choroid in regulating eye growth, the changes in the sclera that lead to axial elongation, gene-environment interactions, and the development of in-vitro experimental models. Furthermore, these funding agencies should target audacious proposals to foster the innovative, multidisciplinary research that is needed to fully harmonize our understanding of the visual information processing by the retina that leads to changes in scleral remodeling. The field of myopia research should adopt an approach that considers the whole retina rather than the fovea alone.
CURRENT AND EMERGING TREATMENT OPTIONS FOR MYOPIA
Conclusions: Treatment options for myopia progression have increased in the last 20 years and include multifocal optical corrections and the sole pharmacological treatment: atropine eye drops. Time outdoors during daylight is an emerging treatment strategy, especially in the younger years. Further research is needed to understand the mechanism of action of the current treatments that have limited effects and can cause rapid eye growth after cessation of treatment. The safety of myopia treatments is paramount due to the probable need for daily applications (e.g., atropine) for a decade or more of life. The current state of knowledge of treatment options reflects our limited understanding of both the fundamental mechanisms of eye length regulation and how treatments act to alter the progression — and perhaps even the onset — of the disease.
Recommendations: Funding agencies, including the National Institutes of Health, Research to Prevent Blindness, and others, should support research to develop new treatment strategies for myopia as well as to determine the mechanisms underlying current treatments. Progress in this area needs intentionally integrated, multidisciplinary research in basic and clinical vision science to understand the mechanisms by which therapies can control eye growth. Scientists should develop treatment strategies to minimize short- and long-term side effects and maximize safety. Funding for multicenter randomized clinical trials should be directed toward longer-term human studies, starting at earlier ages, to determine long-term benefits with respect to ultimate refractive error and ocular health.
IDENTIFYING CHILDREN WITH MYOPIA AND THE LINKS TO TREATMENT: METHODS AND BARRIERS
Conclusions: Multiple socioeconomic barriers to vision care for children exist, with the most significant being an uneven awareness of the importance of checking children’s ocular health, parents’ difficulties in gaining access to an eye care professional, and barriers to compliance with prescribed treatments. Vision screening and referrals are important for identifying children with vision impairment and facilitating access to treatment.
Recommendations: The U.S. Department of Health and Human Services, in collaboration with departments of education at the state level, should take measures to ensure that children receive a vision screening before first grade and a comprehensive eye exam when needed. An integrated, national data surveillance system is needed for collecting state-level data on vision screening, referrals to eye care providers, sociodemographics (age, race/ethnicity, sex, and geographic location), and outcomes of referrals. This data system would not only enhance care integration and communication but also enable monitoring to ensure that follow-up care is received, especially in high-risk populations.
Myopia is a disease with increasing worldwide prevalence and severity. Recognition of the impact of its downstream complications needs to be taken seriously. Notably, the committee recommends that the Centers for Medicare & Medicaid Services classify myopia as a disease and, therefore, a medical diagnosis. This reclassification is to ensure efforts are undertaken not only to treat blurry vision resulting from uncorrected or under-corrected refractive error but also to ensure that stakeholders such as federal and state agencies, professional associations, patients, and caregivers are investing in the prevention and management of myopia. Funding agencies should support innovative, multidisciplinary research to identify mechanisms and novel treatments for myopia. Collaborative efforts involving health care providers, policymakers, researchers, and funding agencies are essential to tackle this disease effectively.
The study was sponsored by the American Academy of Optometry, the American Optometric Association, the Health Care Alliance for Patient Safety, Herbert Wertheim School of Optometry & Vision Science, the University of California, Berkeley, Johnson & Johnson Vision, the National Eye Institute, Reality Labs, Research to Prevent Blindness, and the Warby Parker Impact Foundation.
National Academies of Sciences, Engineering, and Medicine. 2024. Myopia: Causes, Prevention, and Treatment of an Increasingly Common Disease. Washington, DC: The National Academies Press.
DOI: https://doi.org/10.17226/27734.
