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Investigative Ophthalmology & Visual... Feb 2019With 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...
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.
Topics: Animals; Disease Progression; Humans; Internationality; Myopia; Prevalence; Risk Factors; Vision Disorders
PubMed: 30817825
DOI: 10.1167/iovs.18-25980 -
Progress in Retinal and Eye Research Nov 2017In the face of an "epidemic" increase in myopia over the last decades and myopia prevalence predicted to reach 2.5 billion people by the end of this decade, there is an... (Review)
Review
In the face of an "epidemic" increase in myopia over the last decades and myopia prevalence predicted to reach 2.5 billion people by the end of this decade, there is an urgent need to develop effective and safe therapeutic interventions to slow down this "myopia booming" and prevent myopia-related complications and vision loss. Dopamine (DA) is an important neurotransmitter in the retina and mediates diverse functions including retina development, visual signaling, and refractive development. Inspired by the convergence of epidemiological and animal studies in support of the inverse relationship between outdoor activity and risk of developing myopia and by the close biological relationship between light exposure and dopamine release/signaling, we felt it is timely and important to critically review the role of DA in myopia development. This review will revisit several key points of evidence for and against DA mediating light control of myopia: 1) the causal role of extracellular retinal DA levels, 2) the mechanism and action of dopamine D1 and D2 receptors and 3) the roles of cellular/circuit retinal pathways. We examine the experiments that show causation by altering DA, DA receptors and visual pathways using pharmacological, transgenic, or visual environment approaches. Furthermore, we critically evaluate the safety issues of a DA-based treatment strategy and some approaches to address these issues. The review identifies the key questions and challenges in translating basic knowledge on DA signaling and myopia from animal studies into effective pharmacological treatments for myopia in children.
Topics: Dopamine; Dopamine Agonists; Dopamine Antagonists; Eye; Humans; Myopia; Receptors, Dopamine; Retina; Signal Transduction
PubMed: 28602573
DOI: 10.1016/j.preteyeres.2017.06.003 -
Frontiers in Public Health 2022The myopia epidemic has become a global public health problem. Although myopia is progressing worldwide, the recent coronavirus infections 2019 (COVID-19) outbreak has... (Review)
Review
The myopia epidemic has become a global public health problem. Although myopia is progressing worldwide, the recent coronavirus infections 2019 (COVID-19) outbreak has spurred myopia progression. The current evidence-based treatments for humans are atropine eye drops, optical treatment with defocus, use of orthokeratology, extending proximity working distance, pausing from near work every half hour and increased time outside the home. Studies on myopia using animal models have been conducted for more than 40 years. In recent years, new mechanisms of myopia suppression have been revealed from animal experiments such as inflammation control, intraocular pressure control, light control, and the activity of early growth response protein 1 control. This mini-review provides a summary of the scientific evidence currently available on the control of myopia, and the possible treatments mitigating myopia.
Topics: Atropine; COVID-19; Disease Progression; Humans; Myopia; Ophthalmic Solutions
PubMed: 35619815
DOI: 10.3389/fpubh.2022.897600 -
American Journal of Ophthalmology Apr 2022To verify the dose-response relation between the degree of myopia and open-angle glaucoma (OAG) risk DESIGN: Dose-response meta-analysis. (Meta-Analysis)
Meta-Analysis Review
PURPOSE
To verify the dose-response relation between the degree of myopia and open-angle glaucoma (OAG) risk DESIGN: Dose-response meta-analysis.
METHODS
We searched the PubMed, EMBASE, and Cochrane Library databases for population-based studies published until November 30, 2020, and reporting on both myopia and OAG. Random-effect models generated pooled odds ratios (OR) and 95% CIs. Results robustness was confirmed by influence and subgroup analyses. A 2-stage dose-response meta-analysis calculated the OAG risk per unit dose of myopia (spherical equivalent [SE] decrease of 1 diopter [D]) and examined the relationship pattern.
RESULTS
The meta-analysis comprised 24 studies in 11 countries (514,265 individuals). The pooled OR of any myopia degree's association with OAG was 1.88 (95% CI, 1.66-2.13; I = 53%). The OR differences based on ethnicity (Asians vs Westerners) or 5 geographic areas were not statistically significant (P = .80 and P = .06, respectively). The pooled ORs of the associations between low, moderate, moderate-to-high, high myopia, and OAG were 1.50 (95% CI, 1.29-1.76), 1.69 (95% CI, 1.33-2.15), 2.27 (95% CI, 1.74-2.96), and 4.14 (95% CI, 2.57-6.69), respectively. According to the dose-response meta-analysis, the pooled OR (per SE 1-D change) was 1.21 (95% CI, 1.15-1.28). The OAG risk accelerated at approximately -6 D, and further accelerated from -8 D, showing a nonlinear concave upward slope (P = .03).
CONCLUSIONS
For each unit (1-D) increase in myopia, the risk of glaucoma increases by approximately 20%. The risk more steeply increases in high-degree myopia, representing a significant nonlinear relationship.
Topics: Glaucoma; Glaucoma, Open-Angle; Humans; Myopia; Odds Ratio; Refraction, Ocular
PubMed: 34648776
DOI: 10.1016/j.ajo.2021.10.007 -
Frontiers in Immunology 2023As the most common type of refractive error, myopia has become one of the leading causes of visual impairment. With the increasing prevalence of myopia, there is a... (Review)
Review
As the most common type of refractive error, myopia has become one of the leading causes of visual impairment. With the increasing prevalence of myopia, there is a growing need to better understand the factors involved in its development. Inflammation, one of the most fundamental pathophysiological processes in humans, is a rapid response triggered by harmful stimuli and conditions. Although controlled inflammatory responses are necessary, over-activated inflammation is the common soil for many diseases. The impact of inflammation on myopia has received rising attention in recent years. Elevated inflammation may contribute to myopia progression either directly or indirectly by inducing scleral remodeling, and myopia development may also increase ocular inflammation. This article provides a comprehensive review of the interplay between inflammation and myopia and the potential biological mechanisms, which may present new targets for understanding the pathology of myopia and developing myopia therapies.
Topics: Humans; Myopia; Prevalence
PubMed: 37849748
DOI: 10.3389/fimmu.2023.1260592 -
Biomedicine & Pharmacotherapy =... Jan 2022Myopia has become one of the most critical health problems in the world with the increasing time spent indoors and increasing close work. Pathological myopia may have... (Review)
Review
Myopia has become one of the most critical health problems in the world with the increasing time spent indoors and increasing close work. Pathological myopia may have multiple complications, such as myopic macular degeneration, retinal detachment, cataracts, open-angle glaucoma, and severe cases that can cause blindness. Mounting evidence suggests that the cause of myopia can be attributed to the complex interaction of environmental exposure and genetic susceptibility. An increasing number of researchers have focused on the genetic pathogenesis of myopia in recent years. Scleral remodeling and excessive axial elongating induced retina thinning and even retinal detachment are myopia's most important pathological manifestations. The related signaling pathways are indispensable in myopia occurrence and development, such as dopamine, nitric oxide, TGF-β, HIF-1α, etc. We review the current major and recent progress of biomedicine on myopia-related signaling pathways and mechanisms.
Topics: Biomedical Research; Humans; Myopia; Signal Transduction
PubMed: 34861634
DOI: 10.1016/j.biopha.2021.112472 -
Journal of Physiological Anthropology Jan 2024Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of... (Review)
Review
BACKGROUND
Myopia, commonly known as near-sightedness, has emerged as a global epidemic, impacting almost one in three individuals across the world. The increasing prevalence of myopia during early childhood has heightened the risk of developing high myopia and related sight-threatening eye conditions in adulthood. This surge in myopia rates, occurring within a relatively stable genetic framework, underscores the profound influence of environmental and lifestyle factors on this condition. In this comprehensive narrative review, we shed light on both established and potential environmental and lifestyle contributors that affect the development and progression of myopia.
MAIN BODY
Epidemiological and interventional research has consistently revealed a compelling connection between increased outdoor time and a decreased risk of myopia in children. This protective effect may primarily be attributed to exposure to the characteristics of natural light (i.e., sunlight) and the release of retinal dopamine. Conversely, irrespective of outdoor time, excessive engagement in near work can further worsen the onset of myopia. While the exact mechanisms behind this exacerbation are not fully comprehended, it appears to involve shifts in relative peripheral refraction, the overstimulation of accommodation, or a complex interplay of these factors, leading to issues like retinal image defocus, blur, and chromatic aberration. Other potential factors like the spatial frequency of the visual environment, circadian rhythm, sleep, nutrition, smoking, socio-economic status, and education have debatable independent influences on myopia development.
CONCLUSION
The environment exerts a significant influence on the development and progression of myopia. Improving the modifiable key environmental predictors like time spent outdoors and engagement in near work can prevent or slow the progression of myopia. The intricate connections between lifestyle and environmental factors often obscure research findings, making it challenging to disentangle their individual effects. This complexity underscores the necessity for prospective studies that employ objective assessments, such as quantifying light exposure and near work, among others. These studies are crucial for gaining a more comprehensive understanding of how various environmental factors can be modified to prevent or slow the progression of myopia.
Topics: Child, Preschool; Child; Humans; Prospective Studies; Myopia; Refraction, Ocular; Accommodation, Ocular; Circadian Rhythm
PubMed: 38297353
DOI: 10.1186/s40101-024-00354-7 -
JAMA Ophthalmology Jun 2017Some uncertainty about the clinical value and dosing of atropine for the treatment of myopia in children remains. (Meta-Analysis)
Meta-Analysis Review
IMPORTANCE
Some uncertainty about the clinical value and dosing of atropine for the treatment of myopia in children remains.
OBJECTIVE
To evaluate the efficacy vs the adverse effects of various doses of atropine in the therapy for myopia in children.
DATA SOURCES
Data were obtained from PubMed, EMBASE, and the Cochrane Central Register of Controlled Trials, from inception to April 30, 2016. The reference lists of published reviews and clinicaltrials.gov were searched for additional relevant studies. Key search terms included myopia, refractive errors, and atropine. Only studies published in English were included.
STUDY SELECTION
Randomized clinical trials and cohort studies that enrolled patients younger than 18 years with myopia who received atropine in at least 1 treatment arm and that reported the annual rate of myopia progression and/or any adverse effects of atropine therapy were included in the analysis.
DATA EXTRACTION AND SYNTHESIS
Two reviewers independently abstracted the data. Heterogeneity was statistically quantified by Q, H, and I2 statistics, and a meta-analysis was performed using the random-effects model. The Cochrane Collaboration 6 aspects of bias and the Newcastle-Ottawa Scale were used to assess the risk for bias.
MAIN OUTCOMES AND MEASURES
The primary outcome was a difference in efficacy and the presence of adverse effects at different doses of atropine vs control conditions. The secondary outcomes included the differences in adverse effects between Asian and white patients.
RESULTS
Nineteen unique studies involving 3137 unique children were included in the analysis. The weighted mean differences between the atropine and control groups in myopia progression were 0.50 diopters (D) per year (95% CI, 0.24-0.76 D per year) for low-dose atropine, 0.57 D per year (95% CI, 0.43-0.71 D per year) for moderate-dose atropine, and 0.62 D per year (95% CI, 0.45-0.79 D per year) for high-dose atropine (P < .001), which translated to a high effect size (Cohen d, 0.97, 1.76, and 1.94, respectively). All doses of atropine, therefore, were equally beneficial with respect to myopia progression (P = .15). High-dose atropine were associated with more adverse effects, such as the 43.1% incidence of photophobia compared with 6.3% for low-dose atropine and 17.8% for moderate-dose atropine (χ22 = 7.05; P = .03). In addition, differences in the incidence of adverse effects between Asian and white patients were not identified (χ21 = 0.81; P = .37 for photophobia).
CONCLUSIONS AND RELEVANCE
This meta-analysis suggests that the efficacy of atropine is dose independent within this range, whereas the adverse effects are dose dependent.
Topics: Atropine; Child; Disease Progression; Dose-Response Relationship, Drug; Humans; Mydriatics; Myopia; Refraction, Ocular
PubMed: 28494063
DOI: 10.1001/jamaophthalmol.2017.1091 -
Acta Ophthalmologica Nov 2021Myopia is the most common type of refractive errors characterized by excessive elongation of the ocular globe. With the increasing prevalence of myopia, improved... (Review)
Review
Myopia is the most common type of refractive errors characterized by excessive elongation of the ocular globe. With the increasing prevalence of myopia, improved knowledge of factors involved in myopia development is of particular importance. There are growing evidence suggesting that the choroid plays an important role in the regulation of eye growth and the development of myopia. Studies have demonstrated that thinning choroid is a structural feature of myopia, with a negative correlation between choroidal thickness and axial length, suggesting that the change in choroidal thickness may be a predictive biomarker for long-term changes in ocular elongation. Given the fact that the choroid is primarily a vascular structure capable of rapidly changing blood flow, variations of choroidal thickness might be primarily caused by changes in choroidal blood flow. Considering that hypoxia is associated with myopia and choroidal blood flow is the main source of oxygen and nourishment supply, apart from the effect on myopia possibly by changing choroidal thickness, decreasing choroidal blood flow may contribute to scleral ischaemia and hypoxia, resulting in alterations in the scleral structure and thus leading to myopia. This review aims to provide an overview of recent work exploring the influence of the choroid on myopia from perspectives of choroidal thickness and blood flow, which may present new predictive indicators for the onset of myopia and new targets for the development of novel therapeutic approaches for myopia.
Topics: Choroid; Disease Progression; Humans; Myopia; Regional Blood Flow; Tomography, Optical Coherence
PubMed: 33550704
DOI: 10.1111/aos.14773 -
Clinical & Experimental Optometry Jan 2020Orthokeratology has undergone drastic changes since first described in the early 1960s. The original orthokeratology procedure involved a series of lenses to flatten the... (Review)
Review
Orthokeratology has undergone drastic changes since first described in the early 1960s. The original orthokeratology procedure involved a series of lenses to flatten the central cornea and was plagued by variable results. The introduction of highly oxygen-permeable lens materials that can be worn overnight, corneal topography, and reverse-geometry lens designs revolutionised this procedure. Modern overnight orthokeratology causes rapid, reliable, and reversible reductions in refractive error. With modern designs, patients can wear lenses overnight, remove them in the morning, and see clearly throughout the day without the need for daytime refractive correction. Modern reverse-geometry lens designs cause central corneal flattening and mid-peripheral corneal steepening that provides clear foveal vision while simultaneously causing a myopic shift in peripheral retinal defocus. The peripheral myopic retinal defocus caused by orthokeratology is hypothesised to be responsible for reductions in myopia progression in children fitted with these lenses. This paper reviews the changes in orthokeratology lens design that led to the reverse-geometry orthokeratology lenses that are used today and the optical changes these lenses produce. The optical changes reviewed include changes in refractive error and their time course, high- and low-contrast visual acuity changes, changes in higher-order aberrations and visual quality metrics, changes in accommodation, and changes in peripheral defocus caused by orthokeratology. The use of orthokeratology for myopia control in children is also reviewed, as are hypothesised connections between orthokeratology-induced myopic peripheral defocus and slowed myopia progression in children, and safety and complications associated with lens wear. A better understanding of the ocular and optical changes that occur with orthokeratology will be beneficial to both clinicians and patients in making informed decisions regarding the utilisation of orthokeratology. Future research directions with this lens modality are also discussed.
Topics: Contact Lenses; Corneal Wavefront Aberration; Humans; Myopia; Optics and Photonics; Orthokeratologic Procedures; Visual Acuity
PubMed: 31378996
DOI: 10.1111/cxo.12947