Trend Analysis of Global, Regional, and National Burdens of Visual Impairment Due to Refraction Disorders from 1990 to 2021: Findings from the Global Burden of Disease Study 2021

Trend Analysis of Global, Regional, and National Burdens of Visual Impairment Due to Refraction Disorders from 1990 to 2021: Findings from the Global Burden of Disease Study 2021 | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Article Trend Analysis of Global, Regional, and National Burdens of Visual Impairment Due to Refraction Disorders from 1990 to 2021: Findings from the Global Burden of Disease Study 2021 Qing Zhou, Ting Tang, Youran Cai, Yuying Dong, Yuanting Yang, and 1 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-6172901/v1 This work is licensed under a CC BY 4.0 License Status: Posted Version 1 posted You are reading this latest preprint version Abstract Purpose To estimate the global, regional, and national burden of vision impairment due to refraction disorders (RD) from 1990 to 2021 based on sex, age, and Socio-demographic Index (SDI), and to predict future disease trends. Methods This retrospective demographic analysis utilized data from the 2021 Global Burden of Disease (GBD) database. Prevalence, years lived with disability (YLDs), age-standardized prevalence rates (ASPR), and age-standardized YLDs rates (ASYR) of RD from 1990 to 2021 were analyzed to assess temporal, age, and sex-specific trends. We calculated the Average Annual Percentage Change (AAPC) to determine changes in prevalence and YLDs and used the Bayesian Age-Period-Cohort (BAPC) model to forecast the disease burden of RD from 2020 to 2035. Results ASPR and ASYR declined from 1990 to 2021, the AAPC is -3.76 (95% confidence interval [CI]: -4.20~-3.32) and − 0.26 (95% CI: -0.28~-0.25), respectively. In 2021, the global prevalence RD was 159,765,917 (95% uncertainty interval [UI]: 142,526,915 ~ 178,698,348). The prevalence was slightly higher in females than in males, with a higher disease burden among middle-aged and elderly populations. There is a slight negative correlation in regional ASPR (r≈-0.32, P < 0.001), with South Asia exhibiting the highest ASPR (3,398/100,000 people [95% UI: 2992 ~ 3860]). The global prevalence of RD is predicted to increase, while the ASPR is expected to decrease from 2022 to 2035. Conclusion Global prevalence of RD has increased in the past 30 years and is predicted to continue increasing over the next 15 years. There was a heavier burden among females, middle-aged, and elderly populations. Health sciences/Medical research/Epidemiology Health sciences/Diseases/Eye diseases/Refractive errors Health sciences/Health care/Public health/Epidemiology Refraction disorders GBD 2021 Prevalence Years lived with disability Figures Figure 1 Figure 2 Figure 3 Figure 4 Introduction Refraction disorders (RD) is a significant global public health issue 1 , 2 , including myopia, hyperopia, astigmatism, and presbyopia 1 . As a leading cause of visual impairment 3 – 5 , they substantially impact our quality of daily life and impose substantial economic burdens on families and society 6 – 9 . In 2020, approximately 2 billion people experienced blindness or visual impairment globally, including 43.3 million blind individuals. Notably, 1.1 billion people suffered from uncorrected refraction disorders, with 510 million 10 and 484 million experiencing vision impairment due to uncorrected presbyopia and myopia, respectively 2 . Fortunately, RD is the most preventable and treatable visual disorder, unlike irreversible blindness caused by glaucoma, age-related macular degeneration, or diabetic retinopathy 3 , 11 . Appropriate spectacle correction 2 , 7 , 12 can significantly improve best-corrected visual acuity (BCVA), and then effectively alleviate the disease burden. Achieving a 40% improvement in effective refractive error coverage (eREC) (BCVA ≥ 6/12) is one of the World Health Organization's primary objectives for global eye health by 2030 2 , also serving as a crucial strategy for attaining the United Nations Sustainable Development Goals (UNSDG) 13 . ASPR of RD has declined over the past three decades 5 , 14 , 15 due to improved refractive error coverage 2 , 16 . However, the Coronavirus Disease-19 (COVID-19) pandemic has profoundly impacted global health systems by altering lifestyle patterns 17 – 19 and redistributing public health resources. Ophthalmic care has been disproportionately affected worldwide, especially in low- and middle-income countries with limited healthcare infrastructure 5 , resulting in a markable increase in myopia prevalence 18 – 20 and significant socioeconomic consequences. Moreover, global aging indicates that by 2050, the world population will be 9.69 billion 5 and half of the world's population could experience visual impairment 13 . The prevalence continues to increase, which means refraction disorders remain a pressing challenge to be addressed globally. Current research primarily concentrates on the epidemiological trends of blindness and visual impairment across various regions, genders, and age groups from 1990 to 2019. Remarkably, there have been few studies examining the patterns of refraction disorders during the initial two years of the COVID-19 pandemic. Considering that the Global Burden of Disease Study 2021 (GBD 2021) represents one of the initial comprehensive assessments of demographic trends during this critical period 21 , our study utilizes its latest data to examine global, regional, and national patterns of prevalence and years lived with disability (YLDs) due to refraction disorders from 1990 to 2021 across various age groups and Socio-demographic Index (SDI) regions. These findings are intended to offer valuable insights for epidemiological research and health economic policy-making. Methods Data Source The data for this article were obtained from the GBD2021 database( https://vizhub.healthdata.org/gbd-results/ ), which provides cross-sectional estimates of the global burden of 371 diseases and injuries across 204 countries and territories from 1990 to 2021. The original data integrates multiple sources, including national censuses, disease registries, vision screening programs, and epidemiological surveillance data from all countries and regions. Detailed methodologies of the GBD 2021 database have been published in related literature 22 . Data Selection We extracted estimated data from the GBD 2021 database on the prevalence and YLDs due to vision impairment and blindness in 204 countries from 1990 to 2021. The data were stratified by 5 SDI regions (grouping countries with similar levels of economic development), 21 GBD regions (based on geographic and epidemiological characteristics), and 204 countries globally. Additionally, disease burden estimates were categorized by gender (female and male) and age (20 age groups from birth to 95 + years, with 5-year intervals). Data Analysis Data on the number of cases, prevalence, age-standardized prevalence, YLDs, and related rates, as well as percentage changes (PC) from 1990 to 2021, were directly extracted from the GBD2021 database. All rates are reported per 100,000 population. YLDs were calculated by multiplying the prevalence of sequelae for each disease and injury by age, gender, location, and specific year by their respective disability weights 22 . The 95% uncertainty interval (UI) was estimated using 500 repeated draws based on the GBD algorithm, providing the 2.5th and 97.5th percentile ranges 22 . We calculated the average annual percentage change (AAPC), which quantifies trend changes over a fixed interval, representing the geometric mean of annual percentage changes (APCs) within the specified period 23 . Thus, AAPC and its 95% confidence interval (CI) were used to reflect trends. The analysis encompasses the prevalence and trends of refraction disorders across various countries, regions, periods, age groups, and genders, with the results in visual representation. All figures and statistical analyses were conducted using RStudio software (version 4.4.1). Results Global Trends in Prevalence and YLDs of Refraction Disorders From 1990 to 2021, the global prevalence and YLDs of vision impairment due to refraction disorders both exhibited an upward trend (Table 1, Figure 1). The prevalence number increased by 66% (95%UI: 62% ~ 71%), rising from 95,978,319(95%UI: 86,236,197 ~ 106,044,403) in 1990 to 159,765,917 (95%UI: 142,526,915 ~ 178,698,348) in 2021 (Table 1). Similarly, YLDs increased by 64% (95%UI: 61% ~ 68%), from 4,029,084 (95%UI: 2821217 ~ 5812174) in 1990 to 6,618,600 (95%UI: 4,599,082 ~ 9,528,676) in 2021 (Table 1). However, the global ASPR and ASYR of refraction disorders has declined (Table 1, Figure S1, Figure 2), the AAPC of prevalence was −3.76 (95%CI: −4.20 ~ −3.32), decreasing from 2,054/100,000 (95%UI: 1835 ~ 2276) in 1990 to 1,920/100,000 (95% UI: 1,715 ~ 2,135) in 2021 (Table 1); the AAPC of YLDs was −0.26 (95% CI: −0.28 ~ −0.25), declining from 88/100,000 (95%UI: 62 ~ 125) in 1990 to 79/100,000 (95%UI: 55 ~ 114) in 2021 (Table 1). Distribution of Prevalence and YLDs by Age and Gender Subgroup analysis by age revealed that the prevalence number and YLDs increased across all age groups globally, with higher rates among females than males in all age groups (Table 1, Figure 1, Figure 2). The burden of RD was concentrated in individuals aged 45~74 years, with the largest increase observed in the 65~69 age group, rising from 7,245,966 (95%UI: 5,773,134 ~ 9,019,623) in 1990 to 15,108,580 (95% UI: 11,901,920 ~ 19,081,314) in 2021 (Table 1). The prevalence of those aged 65 and above increased by over 100%, with the 95+ age group experiencing a staggering 400% increase (95% UI: 391% ~ 408%). YLDs showed a similar growth trend (Table 1). However, most age groups exhibited a decline in ASPR except for the 20~24, 25~29, 35~39, and 40~45 age groups, which showed an increase. All age groups showed a decline in ASYR (Table 1, Figure 2). The global prevalence and YLDs in males and females both increased from 1990 to 2021, while ASPR and ASYR declined (Table 1, Figure 2). The AAPC of ASPR was −4.67 (95% CI: −5.06 ~ −4.28) for females and −3.21 (95% CI: −3.70 ~ −2.71) for males. The AAPC for ASYR showed a slight decline, with −0.31 (95% CI: −0.32 ~ −0.29) for females and −0.23 (95% CI: −0.25 ~ −0.21) for males (Table 1). Regional analysis indicated that female prevalence was higher than male prevalence in most regions, except in economically developed areas such as Australasia, Western Europe, and high-income Asia-Pacific, where female prevalence was slightly lower than male prevalence (Figure S2). Disease Burden Trends by GBD Region In most of the 21 GBD regions, the prevalence and YLD rates of blindness and vision impairment due to RD declined (Table 1, Figure S2). The South Asia had the highest ASPR and ASYR (Table 1, Figure S2), with prevalence decreasing from 4,446/100,000 in 1990 to 3,398/100,000 in 2021 (Table 1). ASYR in South Asia also declined, from 202/100,000 in 1990 to 142/100,000 in 2021. Notably, South Asia showed the most rapid decline in both ASPR (AAPC = -32.48; 95% CI: -33.34 ~ -31.62) and ASYR (AAPC = -1.89; 95% CI: -1.93 ~ -1.86) (Table 1). In contrast, Australasia, Central Sub-Saharan Africa, High-income North America, and Western Sub-Saharan Africa saw an increase in prevalence. Additionally, Central Sub-Saharan Africa and Western Sub-Saharan Africa showed rising ASYR (Table 1, Figure S2). Meanwhile, High-income North America had the lowest ASPR and ASYR (Table 1, Figure S2), with ASPR increasing slightly from 1,051/100,000 in 1990 to 1,066/100,000 in 2021, and ASYR remaining stable at around 40/100,000 in both years. Western Sub-Saharan Africa showed a significant increase in ASPR (AAPC = 4.70; 95% CI: 4.53 ~ 4.87) and a slight rise in ASYR (AAPC = 0.18; 95% CI: 0.17 ~ 0.18) (Table 1). Disease Burden Trends by SDI Region To better illustrate the developmental disparities among different regions and countries, SDI (a composite measure of per capita income for individuals under 15, average years of education for females aged 15 and above, and total fertility rate for females under 25) was used to assess economic levels and development status. From 1990 to 2021, the global prevalence of RD significantly declined, except in high SDI regions, where it increased. The most pronounced decline was observed in low-middle SDI regions. Similarly, ASYR remained stable in high SDI regions but declined in the other four SDI regions (Table 1, Figure S1). In addition to the increase in high SDI regions, there was a significant decline in medium-high SDI, medium SDI, medium-low SDI, and low SDI regions, with the most pronounced decrease observed in medium-low SDI regions; the YLDs rate showed no significant change in high SDI regions, while it exhibited a downward trend in the other four SDI regions. Additionally, there was a significant decline in vision impairment in High-middle, middle, Low-middle, and Low SDI regions, with the most pronounced decrease observed in medium-low SDI regions. In contrast, the ASYR showed no significant change in High SDI regions, while it exhibited a downward trend in the other four SDI regions. Due to varying population distributions and epidemiological trends across GBD regions, we examined the ASR trends for RD based on the 21 GBD regions. Overall, a slight negative correlation was observed between ASPR and SDI (r≈-0.32, P <0.001) (Figure 3A). Regions such as High-income North America, Western Europe, and Central Asia exhibited stable trends with ASPR lower than expected. However, in many low- and middle-SDI regions, ASPR showed significant fluctuations and was higher than anticipated, particularly in South Asia. In Southeast Asia, the overall ASR was lower than expected but displayed a declining trend (Table 1, Figure 3A). At the national level, in 2021, there was no significant correlation between ASPR of refraction disorders and SDI in most countries ( P > 0.05) (Figure 3B). Prediction of Global Prevalence of Refraction Disorders from 2022 to 2035 Utilizing the BAPC package in R software, we predicted the prevalence trends of refraction disorders over the next 15 years (Figure 4). Globally, the prevalence number of vision impairment due to refraction disorders is anticipated to increase from 2022 to 2035, whereas the ASPR is predicted to decrease (Figure 4). By 2035, the prevalence is expected to reach 196.87 million, an approximate rise of 37.11 million from 2021 (Table S2). The ASPR is anticipated to be around 1,890/100,000. Gender analysis revealed that females remain the predominant group affected by refraction disorders, accounting for 54% of the total cases. The number of females is predicted to reach 106.52 million, with ASPR of 1,995/100,000, while males is expected to be 90.35 million, with ASPR of 1,783/100,000 (Table S1). Age subgroup analysis indicated that, except for the <5 and 5~9 age groups, all other age groups are expected to see an increase in prevalence. Over the next 15 years, the primary affected population will remain 50~79 age subgroups, with the highest prevalence observed in the 60~64 and 65~69 age subgroups (Figures S4 and S5). Discussion Although there were 159.76 million people with RD worldwide in 2021, the ASPR and ASYR have decreased. This suggests that the increase in the prevalence may be closely related to population growth and global population aging 3 , 10 . The global burden of RD is significantly higher among the elderly, females, and populations in lower SDI regions, highlighting persistent socioeconomic, gender, and age disparities. According to the BAPC model, the prevalence of RD continues to rise while the ASPR is going to decline from 2022 to 2035. RD is a leading cause of blindness and vision impairment globally 1 – 3 . The United Nations’ 2030 Agenda for Sustainable Development emphasizes ‘Vision for Everyone’ and advocates for person-centered integrated eye care, including preventable blindness and vision impairment 13 . Additionally, the World Health Organization’s 2030 Global Eye Care Targets report also emphasizes the importance of preventable blindness and vision impairment by outlining two key goals: increasing effective cataract surgery coverage (eCSC) by 30% and eREC by 40% 2 . In response to these declarations, governments and relevant organizations have strongly supported the development of public health policies through regular vision screenings in schools and communities, improved eye care services, and heightened public awareness of prevention and timely intervention have significantly enhanced the basic healthcare environment for individuals with RD. These efforts may explain why, despite the global increase in prevalence from 1990 to 2021, the ASPR and ASYR of RD have declined, with a corresponding decrease in the AAPC. Our findings are consistent with previous reports analyzing GBD data from 1990 to 2019 14 . Our study found that females are more susceptible to refraction disorders than males, particularly in low SDI regions and among individuals aged 50 and above. In high SDI regions, no significant gender disparity was observed, indicating that such inequality is influenced by socioeconomic development levels and age 24 , 25 . Notably, gender inequality in the global burden of refraction disorders has persisted over the past few decades 24 , and limiting gender disparities is a crucial component of achieving the United Nations Sustainable Development Goals 25 , necessitating the formulation of gender-sensitive health policies 24 . The disease burden among the elderly population should not be ignored and deserves attention. Studies show that 23% of the global disease burden occurs in the elderly, accounting for approximately half of the burden in high-income countries and one-fifth in low- and middle-income countries 26 . By 2050, it is predicted that 866 million people will have uncorrected presbyopia 10 . This population faces an increased risk of refraction disorders 27 , cataracts, age-related macular degeneration, glaucoma, and diabetic retinopathy. Many elderly people fail to achieve satisfactory vision even after refractive correction, suggesting the presence of multiple coexisting eye conditions in those people. However, the coverage of healthcare resources for the elderly is particularly inadequate, exacerbating insufficient social security and limiting access to eye care services, creating a vicious cycle. Therefore, enhancing the scope and quality of eye care services is essential for reducing the global burden of vision impairment among the elderly 28 . Overall, regions with lower socioeconomic status bear a heavier disease burden. However, studies have shown that patients with presbyopia in some developed countries can access appropriate optical corrections 29 . In low SDI regions, the disease burden is constrained by economic limitations and, to some extent, linked to education levels 27 . Insufficient awareness of the disease, coupled with a lack of local public health resources and financial constraints, makes it difficult for individuals to afford glasses or refractive correction surgeries. Nevertheless, it is encouraging that the global health inequality concentration index has declined from 1990 to 2021, indicating a relative reduction in disparities between countries and regions. However, the COVID-19 pandemic, which has spread globally, has threatened human health and safety. It has not only disrupted basic healthcare services but also altered public lifestyles. The demand for near-distance work activities has increased, and the use of electronic devices has significantly risen 17 , 30 , while outdoor time has decreased. These factors have further contributed to the rising prevalence of RD 17 – 19 . Therefore, it is crucial to recognize the impact of COVID-19 on the health, social, and economic conditions of individuals with vision impairment. Moving forward, implementing eye health strategies tailored to different populations, regions, and genders, expanding community and school screening coverage, increasing financial investment in eye health initiatives, and enhancing access to comprehensive eye care services are essential steps to take effective action toward achieving the UNSDG. Limitations Our study has several limitations. First, although the GBD 2021 database provides comprehensive retrospective data, significant variations in healthcare standards and research methodologies across regions may introduce bias, potentially affecting the accuracy of the data. Therefore, further optimization of data quality is necessary. Second, clinical methods for measuring vision have evolved, particularly before the 21st century, when measurement techniques were less standardized. This may result in inaccuracies in the disease burden data of RD over the past 30 years. Additionally, differences in measurement methods across countries and regions could lead to discrepancies between years and areas. Thus, future research should aim to establish standardized and consistent vision measurement methods globally. Furthermore, a patient may simultaneously have multiple eye diseases, such as cataracts combined with presbyopia, myopia combined with high myopia fundus lesions, etc., which increases the difficulty in diagnosing the main causes of visual impairment and blindness. Another limitation is that the COVID-19 pandemic has significantly altered lifestyles and healthcare-seeking behaviors worldwide, potentially impacting the accuracy of the 2021 disease burden data. This may cause bias in our predictions. In light of these issues, future research should focus on prospective studies to enhance the rigor and reliability of findings, thereby better exploring the epidemiological characteristics of RD globally. Additionally, more specific eye conditions should be considered to accurately describe the burden of refraction disorders across different age groups. Conclusion By conducting subgroup analyses of prevalence and YLDs across different age groups, genders, regions, countries, and SDI levels, this study provides a comprehensive and detailed analysis of the global burden of RD from 1990 to 2021. Using the BAPC model, we further predicted the global disease burden during 2022 ~ 2035. Our findings indicate that the global burden of RD has improved over the past 30 years. However, the increasing prevalence due to global population growth and aging underscores that RD remains a significant public health challenge that cannot be ignored. Moreover, substantial disparities persist across age groups, genders, GBD regions, countries, and SDI levels. Therefore, targeted interventions and high-quality services are needed for those subgroups. In summary, our results highlight the burden of RD across different populations and regions, aiming to raise public awareness of this issue. Our study aims to support future disease screening and policy-making, with the hope of further reducing the global burden. Declarations Author contributions TT designed the study and searched the data. YC, YD, WQ and YY collated the data. TT, YC, and YD performed analysis and wrote the manuscript. QZ reviewed the statistical analysis and manuscript. All authors reviewed and agreed on the final version of the manuscript. Acknowledgments We thank all the participants and staff for their dedication and contributions. We thank Bullet Edits Limited for the linguistic editing and proofreading of the manuscript. Data availability statement All the data of our study is available from https://vizhub.healthdata.org/gbd-results/. Ethical Approval Not applicable. Funding No funding. Conflict of interest statement The authors declare no competing financial interests. References Schiefer U, Kraus C, Baumbach P, et al. Refractive errors[J]. 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Additional Declarations There is no conflict of interest Supplementary Files Table1.docx TableS1.docx Table S1 Global prevalence of refraction disorders in all age groups based on the BAPC model predictions FigureS1.pdf Figure S1 Global and 5 SDI regions age-standardized rate trends of prevalence (A) and years lived with disability (YLDs) (B) from 1990 to 2021 FigureS2.pdf Figure S2 The prevalence number (A, C) and percentage (B, D) of refraction disor-ders by GBD regions and sexes in 1990 and 2021 FigureS3.pdf Figure S3 Age-standardized rate of prevalence (A) and YLDs (B) of refraction disorders by GBD regions and ages in 2021 FigureS4.pdf Figure S4 Global prevalence number of refraction disorders in all age groups based on the BAPC model predictions FigureS5.pdf Figure S5 Global age-standardized prevalence rate of refraction disorders in all age groups based on the BAPC model predictions Cite Share Download PDF Status: Posted Version 1 posted You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. 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Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-6172901","acceptedTermsAndConditions":true,"allowDirectSubmit":true,"archivedVersions":[],"articleType":"Article","associatedPublications":[],"authors":[{"id":446127459,"identity":"00b93d6e-e392-4326-af70-6056bd92798f","order_by":0,"name":"Qing Zhou","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAuElEQVRIiWNgGAWjYBACCQh1QI6Nvf0AaVqM+XjOJJCmJXGehIMBcVok23uffeb5cye9TYIhgeFHxTbCWqR5jhvP5uF5ltsm3XiAsefMbcJa5CTSmJl5JA7ntskcSGBmbCNGi/wzoBaDw+lsEgkGxGmRlmADakk4nEC8FsmeNGbGOQcOG7YBA/kgUX6ROH6MmeHNn8Py8u3tBx/8qCBCCwgw8UAZB4hTDwSMP4hWOgpGwSgYBSMSAAAupDew6h8h9wAAAABJRU5ErkJggg==","orcid":"","institution":"The First Affiliated Hospital of Jinan University","correspondingAuthor":true,"prefix":"","firstName":"Qing","middleName":"","lastName":"Zhou","suffix":""},{"id":446127460,"identity":"2c9adc10-dcb7-4956-851a-4ab69840a65f","order_by":1,"name":"Ting Tang","email":"","orcid":"","institution":"The First Affiliated Hospital of Jinan University(Guangzhou Overseas Chinese Hospital)","correspondingAuthor":false,"prefix":"","firstName":"Ting","middleName":"","lastName":"Tang","suffix":""},{"id":446127461,"identity":"a6bc5901-0518-4c9a-a7fe-f7371f38e266","order_by":2,"name":"Youran Cai","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Youran","middleName":"","lastName":"Cai","suffix":""},{"id":446127462,"identity":"35dc96dc-3d7a-498f-991d-801196868314","order_by":3,"name":"Yuying Dong","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yuying","middleName":"","lastName":"Dong","suffix":""},{"id":446127463,"identity":"74e1d390-1239-411c-891a-1a4d15231d97","order_by":4,"name":"Yuanting Yang","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Yuanting","middleName":"","lastName":"Yang","suffix":""},{"id":446127464,"identity":"a465265d-9023-48a2-8871-b19092052b9a","order_by":5,"name":"Wanlu Qiu","email":"","orcid":"","institution":"","correspondingAuthor":false,"prefix":"","firstName":"Wanlu","middleName":"","lastName":"Qiu","suffix":""}],"badges":[],"createdAt":"2025-03-06 18:25:37","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-6172901/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-6172901/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":81444709,"identity":"53b27c45-7425-4d4b-bea5-df95c566b4f7","added_by":"auto","created_at":"2025-04-26 15:59:38","extension":"jpg","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":538270,"visible":true,"origin":"","legend":"\u003cp\u003eGlobal maps of prevalence percentage changes (PC) in prevalence rates (A), years lived with disability (YLDs) rates (B), males (C) and females (D) from 1990 to 2021\u003c/p\u003e","description":"","filename":"Figure1.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/cf870a0f1366652242055e03.jpg"},{"id":81444880,"identity":"8469de30-32c9-4f2d-b03b-2ff71165bdab","added_by":"auto","created_at":"2025-04-26 16:07:38","extension":"jpg","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":715540,"visible":true,"origin":"","legend":"\u003cp\u003eGlobal trends in the prevalence of refraction disorders (A) and the age-standardized rate of years lived with disability (YLDs) (B) by sex from 1990 to 2021 Global distribution of age subgroups of the burden of sex-specific refraction disorders in 1990 and 2021. Prevalence (C, D) and age-standardized rate of years lived with disability (YLDs) (E, F). The shadows represent the upper and lower limits of the 95% UI.\u003c/p\u003e","description":"","filename":"Figure2.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/d2c9f80f6dd9465910bc0fd6.jpg"},{"id":81444711,"identity":"860f2a30-068f-4de8-b6f0-bcb006f0541c","added_by":"auto","created_at":"2025-04-26 15:59:38","extension":"jpg","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":250206,"visible":true,"origin":"","legend":"\u003cp\u003eAge-standardized prevalence rate trends in refraction disorders by sociodemographic index: A. 21 GBD regions during 1990 ~ 2021; B. 204 countries and territories in 2021. Expected values for sociodemographic indices and disease prevalence based on all sites are shown as blue lines, shadows represent 95% UI.\u003c/p\u003e","description":"","filename":"Figure3.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/28358927fff2b8c2769eb4d1.jpg"},{"id":81444882,"identity":"51e01503-ae52-4854-83e1-5e448e02190f","added_by":"auto","created_at":"2025-04-26 16:07:38","extension":"jpg","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":164396,"visible":true,"origin":"","legend":"\u003cp\u003eGlobal prevalence number of refraction disorders in all age groups based on the BAPC model predictions: 2022-2035\u003c/p\u003e","description":"","filename":"Figure4.jpg","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/2bfc61c345839e92484bb209.jpg"},{"id":94822704,"identity":"47773fa5-90f4-4291-932f-d0e608471c86","added_by":"auto","created_at":"2025-10-31 06:42:26","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":2242597,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/63e2eb9b-989f-438f-978d-82d5a9531329.pdf"},{"id":81444878,"identity":"8f631fd7-f4fe-4864-974d-1f19f1dfd33e","added_by":"auto","created_at":"2025-04-26 16:07:38","extension":"docx","order_by":1,"title":"","display":"","copyAsset":false,"role":"supplement","size":37353,"visible":true,"origin":"","legend":"","description":"","filename":"Table1.docx","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/01c780f9f9d60dc4469430f0.docx"},{"id":81445437,"identity":"37c35778-d69f-4ca9-8a88-32f7309a5008","added_by":"auto","created_at":"2025-04-26 16:15:38","extension":"docx","order_by":2,"title":"","display":"","copyAsset":false,"role":"supplement","size":26475,"visible":true,"origin":"","legend":"Table S1 Global prevalence of refraction disorders in all age groups based on the BAPC model predictions","description":"","filename":"TableS1.docx","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/7871babfbcd453c95a4c6bd6.docx"},{"id":81445439,"identity":"e57dd331-9e88-4a01-b532-d283c4cc5b5c","added_by":"auto","created_at":"2025-04-26 16:15:38","extension":"pdf","order_by":3,"title":"","display":"","copyAsset":false,"role":"supplement","size":97167,"visible":true,"origin":"","legend":"Figure S1 Global and 5 SDI regions age-standardized rate trends of prevalence (A) and years lived with disability (YLDs) (B) from 1990 to 2021","description":"","filename":"FigureS1.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/eb4f84f7104d16473b662f4b.pdf"},{"id":81444884,"identity":"0977c30d-9d8a-4fd5-9557-3fadf52986df","added_by":"auto","created_at":"2025-04-26 16:07:38","extension":"pdf","order_by":4,"title":"","display":"","copyAsset":false,"role":"supplement","size":266484,"visible":true,"origin":"","legend":"Figure S2 The prevalence number (A, C) and percentage (B, D) of refraction disor-ders by GBD regions and sexes in 1990 and 2021","description":"","filename":"FigureS2.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/655a1fa28b057a5e9d2dbcc0.pdf"},{"id":81444718,"identity":"364e2d54-602e-42f2-93ae-698f295fc65e","added_by":"auto","created_at":"2025-04-26 15:59:38","extension":"pdf","order_by":5,"title":"","display":"","copyAsset":false,"role":"supplement","size":153965,"visible":true,"origin":"","legend":"Figure S3 Age-standardized rate of prevalence (A) and YLDs (B) of refraction disorders by GBD regions and ages in 2021","description":"","filename":"FigureS3.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/0756dfe79355ca328df271e8.pdf"},{"id":81444714,"identity":"a427c966-a681-4170-a631-eecb4002c0f9","added_by":"auto","created_at":"2025-04-26 15:59:38","extension":"pdf","order_by":6,"title":"","display":"","copyAsset":false,"role":"supplement","size":67770,"visible":true,"origin":"","legend":"\u003cp\u003eFigure S4 Global prevalence number of refraction disorders in all age groups based on the BAPC model predictions\u003c/p\u003e","description":"","filename":"FigureS4.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/188837c7ad4ee4537bc5df05.pdf"},{"id":81444715,"identity":"2c4e4f4c-8923-4347-bd07-23ae6fe1f2a4","added_by":"auto","created_at":"2025-04-26 15:59:38","extension":"pdf","order_by":7,"title":"","display":"","copyAsset":false,"role":"supplement","size":67449,"visible":true,"origin":"","legend":"Figure S5 Global age-standardized prevalence rate of refraction disorders in all age groups based on the BAPC model predictions","description":"","filename":"FigureS5.pdf","url":"https://assets-eu.researchsquare.com/files/rs-6172901/v1/e1673b1b8e961a18696ac370.pdf"}],"financialInterests":"There is no conflict of interest","formattedTitle":"Trend Analysis of Global, Regional, and National Burdens of Visual Impairment Due to Refraction Disorders from 1990 to 2021: Findings from the Global Burden of Disease Study 2021","fulltext":[{"header":"Introduction","content":"\u003cp\u003eRefraction disorders (RD) is a significant global public health issue\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e, \u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e, including myopia, hyperopia, astigmatism, and presbyopia\u003csup\u003e\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u003c/sup\u003e. As a leading cause of visual impairment\u003csup\u003e\u003cspan additionalcitationids=\"CR4\" citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e, they substantially impact our quality of daily life and impose substantial economic burdens on families and society\u003csup\u003e\u003cspan additionalcitationids=\"CR7 CR8\" citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e\u003c/sup\u003e. In 2020, approximately 2\u0026nbsp;billion people experienced blindness or visual impairment globally, including 43.3\u0026nbsp;million blind individuals. Notably, 1.1\u0026nbsp;billion people suffered from uncorrected refraction disorders, with 510\u0026nbsp;million \u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003eand 484\u0026nbsp;million experiencing vision impairment due to uncorrected presbyopia and myopia, respectively\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e\u003c/sup\u003e. Fortunately, RD is the most preventable and treatable visual disorder, unlike irreversible blindness caused by glaucoma, age-related macular degeneration, or diabetic retinopathy\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e, \u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e\u003c/sup\u003e. Appropriate spectacle correction\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e, \u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e\u003c/sup\u003e can significantly improve best-corrected visual acuity (BCVA), and then effectively alleviate the disease burden. Achieving a 40% improvement in effective refractive error coverage (eREC) (BCVA\u0026thinsp;\u0026ge;\u0026thinsp;6/12) is one of the World Health Organization's primary objectives for global eye health by 2030 \u003csup\u003e2\u003c/sup\u003e, also serving as a crucial strategy for attaining the United Nations Sustainable Development Goals (UNSDG)\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eASPR of RD has declined over the past three decades \u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e, \u003cspan citationid=\"CR14\" class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan citationid=\"CR15\" class=\"CitationRef\"\u003e15\u003c/span\u003e\u003c/sup\u003e due to improved refractive error coverage\u003csup\u003e\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e, \u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e\u003c/sup\u003e. However, the Coronavirus Disease-19 (COVID-19) pandemic has profoundly impacted global health systems by altering lifestyle patterns\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e and redistributing public health resources. Ophthalmic care has been disproportionately affected worldwide, especially in low- and middle-income countries with limited healthcare infrastructure\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e, resulting in a markable increase in myopia prevalence\u003csup\u003e\u003cspan additionalcitationids=\"CR19\" citationid=\"CR18\" class=\"CitationRef\"\u003e18\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e\u003c/sup\u003e and significant socioeconomic consequences. Moreover, global aging indicates that by 2050, the world population will be 9.69 billion\u003csup\u003e\u003cspan citationid=\"CR5\" class=\"CitationRef\"\u003e5\u003c/span\u003e\u003c/sup\u003e and half of the world's population could experience visual impairment\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. The prevalence continues to increase, which means refraction disorders remain a pressing challenge to be addressed globally.\u003c/p\u003e \u003cp\u003eCurrent research primarily concentrates on the epidemiological trends of blindness and visual impairment across various regions, genders, and age groups from 1990 to 2019. Remarkably, there have been few studies examining the patterns of refraction disorders during the initial two years of the COVID-19 pandemic. Considering that the Global Burden of Disease Study 2021 (GBD 2021) represents one of the initial comprehensive assessments of demographic trends during this critical period\u003csup\u003e\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e\u003c/sup\u003e, our study utilizes its latest data to examine global, regional, and national patterns of prevalence and years lived with disability (YLDs) due to refraction disorders from 1990 to 2021 across various age groups and Socio-demographic Index (SDI) regions. These findings are intended to offer valuable insights for epidemiological research and health economic policy-making.\u003c/p\u003e"},{"header":"Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eData Source\u003c/h2\u003e \u003cp\u003eThe data for this article were obtained from the GBD2021 database(\u003cspan class=\"ExternalRef\"\u003e\u003cspan class=\"RefSource\"\u003ehttps://vizhub.healthdata.org/gbd-results/\u003c/span\u003e\u003cspan address=\"https://vizhub.healthdata.org/gbd-results/\" targettype=\"URL\" class=\"RefTarget\"\u003e\u003c/span\u003e\u003c/span\u003e), which provides cross-sectional estimates of the global burden of 371 diseases and injuries across 204 countries and territories from 1990 to 2021. The original data integrates multiple sources, including national censuses, disease registries, vision screening programs, and epidemiological surveillance data from all countries and regions. Detailed methodologies of the GBD 2021 database have been published in related literature\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003c/div\u003e\n\u003ch3\u003eData Selection\u003c/h3\u003e\n\u003cp\u003eWe extracted estimated data from the GBD 2021 database on the prevalence and YLDs due to vision impairment and blindness in 204 countries from 1990 to 2021. The data were stratified by 5 SDI regions (grouping countries with similar levels of economic development), 21 GBD regions (based on geographic and epidemiological characteristics), and 204 countries globally. Additionally, disease burden estimates were categorized by gender (female and male) and age (20 age groups from birth to 95\u0026thinsp;+\u0026thinsp;years, with 5-year intervals).\u003c/p\u003e \u003cdiv id=\"Sec5\" class=\"Section2\"\u003e \u003ch2\u003eData Analysis\u003c/h2\u003e \u003cp\u003eData on the number of cases, prevalence, age-standardized prevalence, YLDs, and related rates, as well as percentage changes (PC) from 1990 to 2021, were directly extracted from the GBD2021 database. All rates are reported per 100,000 population. YLDs were calculated by multiplying the prevalence of sequelae for each disease and injury by age, gender, location, and specific year by their respective disability weights\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. The 95% uncertainty interval (UI) was estimated using 500 repeated draws based on the GBD algorithm, providing the 2.5th and 97.5th percentile ranges\u003csup\u003e\u003cspan citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u003c/sup\u003e. We calculated the average annual percentage change (AAPC), which quantifies trend changes over a fixed interval, representing the geometric mean of annual percentage changes (APCs) within the specified period\u003csup\u003e\u003cspan citationid=\"CR23\" class=\"CitationRef\"\u003e23\u003c/span\u003e\u003c/sup\u003e. Thus, AAPC and its 95% confidence interval (CI) were used to reflect trends.\u003c/p\u003e \u003cp\u003eThe analysis encompasses the prevalence and trends of refraction disorders across various countries, regions, periods, age groups, and genders, with the results in visual representation. All figures and statistical analyses were conducted using RStudio software (version 4.4.1).\u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cp\u003e\u003cstrong\u003eGlobal Trends in Prevalence and YLDs of Refraction Disorders\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eFrom 1990 to 2021, the global prevalence and YLDs of vision impairment due to refraction disorders both exhibited an upward trend (Table 1, Figure 1). The prevalence number increased by 66% (95%UI: 62% ~ 71%), rising from 95,978,319(95%UI: 86,236,197 ~ 106,044,403) in 1990 to 159,765,917 (95%UI: 142,526,915 ~ 178,698,348) in 2021 (Table 1). Similarly, YLDs increased by 64% (95%UI: 61% ~ 68%), from 4,029,084 (95%UI: 2821217 ~ 5812174) in 1990 to 6,618,600 (95%UI: 4,599,082 ~ 9,528,676) in 2021 (Table 1). However, the global ASPR and ASYR of refraction disorders has declined (Table 1, Figure S1, Figure 2), the AAPC of prevalence was \u0026minus;3.76 (95%CI: \u0026minus;4.20 ~ \u0026minus;3.32), decreasing from 2,054/100,000 (95%UI: 1835 ~ 2276) in 1990 to 1,920/100,000 (95% UI: 1,715 ~ 2,135) in 2021 (Table 1); the AAPC of YLDs was \u0026minus;0.26 (95% CI: \u0026minus;0.28 ~ \u0026minus;0.25), declining from 88/100,000 (95%UI: 62 ~ 125) in 1990 to 79/100,000 (95%UI: 55 ~ 114) in 2021 (Table 1).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDistribution of Prevalence and YLDs by Age and Gender\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eSubgroup analysis by age revealed that the prevalence number and YLDs increased across all age groups globally, with higher rates among females than males in all age groups (Table 1, Figure 1, Figure 2). The burden of RD was concentrated in individuals aged 45~74 years, with the largest increase observed in the 65~69 age group, rising from 7,245,966 (95%UI: 5,773,134 ~ 9,019,623) in 1990 to 15,108,580 (95% UI: 11,901,920 ~ 19,081,314) in 2021 (Table 1). The prevalence of those aged 65 and above increased by over 100%, with the 95+ age group experiencing a staggering 400% increase (95% UI: 391% ~ 408%). YLDs showed a similar growth trend (Table 1). However, most age groups exhibited a decline in ASPR except for the 20~24, 25~29, 35~39, and 40~45 age groups, which showed an increase. All age groups showed a decline in ASYR (Table 1, Figure 2).\u0026nbsp;\u003c/p\u003e\n\u003cp\u003eThe global prevalence and YLDs in males and females both increased from 1990 to 2021, while ASPR and ASYR declined (Table 1, Figure 2). The AAPC of ASPR was \u0026minus;4.67 (95% CI: \u0026minus;5.06 ~ \u0026minus;4.28) for females and \u0026minus;3.21 (95% CI: \u0026minus;3.70 ~ \u0026minus;2.71) for males. The AAPC for ASYR showed a slight decline, with \u0026minus;0.31 (95% CI: \u0026minus;0.32 ~ \u0026minus;0.29) for females and \u0026minus;0.23 (95% CI: \u0026minus;0.25 ~ \u0026minus;0.21) for males (Table 1). Regional analysis indicated that female prevalence was higher than male prevalence in most regions, except in economically developed areas such as Australasia, Western Europe, and high-income Asia-Pacific, where female prevalence was slightly lower than male prevalence (Figure S2).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisease Burden Trends by GBD Region\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eIn most of the 21 GBD regions, the prevalence and YLD rates of blindness and vision impairment due to RD declined (Table 1, Figure S2). The South Asia had the highest ASPR and ASYR (Table 1, Figure S2), with prevalence decreasing from 4,446/100,000 in 1990 to 3,398/100,000 in 2021 (Table 1). ASYR in South Asia also declined, from 202/100,000 in 1990 to 142/100,000 in 2021. Notably, South Asia showed the most rapid decline in both ASPR (AAPC = -32.48; 95% CI: -33.34 ~ -31.62) and ASYR (AAPC = -1.89; 95% CI: -1.93 ~ -1.86) (Table 1). In contrast, Australasia, Central Sub-Saharan Africa, High-income North America, and Western Sub-Saharan Africa saw an increase in prevalence. Additionally, Central Sub-Saharan Africa and Western Sub-Saharan Africa showed rising ASYR (Table 1, Figure S2). Meanwhile, High-income North America had the lowest ASPR and ASYR (Table 1, Figure S2), with ASPR increasing slightly from 1,051/100,000 in 1990 to 1,066/100,000 in 2021, and ASYR remaining stable at around 40/100,000 in both years. Western Sub-Saharan Africa showed a significant increase in ASPR (AAPC = 4.70; 95% CI: 4.53 ~ 4.87) and a slight rise in ASYR (AAPC = 0.18; 95% CI: 0.17 ~ 0.18) (Table 1).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eDisease Burden Trends by SDI Region\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTo better illustrate the developmental disparities among different regions and countries, SDI (a composite measure of per capita income for individuals under 15, average years of education for females aged 15 and above, and total fertility rate for females under 25) was used to assess economic levels and development status. From 1990 to 2021, the global prevalence of RD significantly declined, except in high SDI regions, where it increased. The most pronounced decline was observed in low-middle SDI regions. Similarly, ASYR remained stable in high SDI regions but declined in the other four SDI regions (Table 1, Figure S1).\u003c/p\u003e\n\u003cp\u003eIn addition to the increase in high SDI regions, there was a significant decline in medium-high SDI, medium SDI, medium-low SDI, and low SDI regions, with the most pronounced decrease observed in medium-low SDI regions; the YLDs rate showed no significant change in high SDI regions, while it exhibited a downward trend in the other four SDI regions. Additionally, there was a significant decline in vision impairment in High-middle, middle, Low-middle, and Low SDI regions, with the most pronounced decrease observed in medium-low SDI regions. In contrast, the ASYR showed no significant change in High SDI regions, while it exhibited a downward trend in the other four SDI regions.\u003c/p\u003e\n\u003cp\u003eDue to varying population distributions and epidemiological trends across GBD regions, we examined the ASR trends for RD based on the 21 GBD regions. Overall, a slight negative correlation was observed between ASPR and SDI (r\u0026asymp;-0.32, \u003cem\u003eP\u003c/em\u003e\u0026lt;0.001) (Figure 3A). Regions such as High-income North America, Western Europe, and Central Asia exhibited stable trends with ASPR lower than expected. However, in many low- and middle-SDI regions, ASPR showed significant fluctuations and was higher than anticipated, particularly in South Asia. In Southeast Asia, the overall ASR was lower than expected but displayed a declining trend (Table 1, Figure 3A). At the national level, in 2021, there was no significant correlation between ASPR of refraction disorders and SDI in most countries (\u003cem\u003eP\u003c/em\u003e \u0026gt; 0.05) (Figure 3B). \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp; \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003ePrediction of Global Prevalence of Refraction Disorders from 2022 to 2035\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eUtilizing the BAPC package in R software, we predicted the prevalence trends of refraction disorders over the next 15 years (Figure 4). Globally, the prevalence number of vision impairment due to refraction disorders is anticipated to increase from 2022 to 2035, whereas the ASPR is predicted to decrease (Figure 4). By 2035, the prevalence is expected to reach 196.87 million, an approximate rise of 37.11 million from 2021 (Table S2). The ASPR is anticipated to be around 1,890/100,000. Gender analysis revealed that females remain the predominant group affected by refraction disorders, accounting for 54% of the total cases. The number of females is predicted to reach 106.52 million, with ASPR of 1,995/100,000, while males is expected to be 90.35 million, with ASPR of 1,783/100,000 (Table S1). Age subgroup analysis indicated that, except for the \u0026lt;5 and 5~9 age groups, all other age groups are expected to see an increase in prevalence. Over the next 15 years, the primary affected population will remain 50~79 age subgroups, with the highest prevalence observed in the 60~64 and 65~69 age subgroups (Figures S4 and S5).\u003c/p\u003e"},{"header":"Discussion","content":"\u003cp\u003eAlthough there were 159.76\u0026nbsp;million people with RD worldwide in 2021, the ASPR and ASYR have decreased. This suggests that the increase in the prevalence may be closely related to population growth and global population aging\u003csup\u003e\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e,\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. The global burden of RD is significantly higher among the elderly, females, and populations in lower SDI regions, highlighting persistent socioeconomic, gender, and age disparities. According to the BAPC model, the prevalence of RD continues to rise while the ASPR is going to decline from 2022 to 2035.\u003c/p\u003e \u003cp\u003eRD is a leading cause of blindness and vision impairment globally\u003csup\u003e\u003cspan additionalcitationids=\"CR2\" citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e\u003c/sup\u003e. The United Nations\u0026rsquo; 2030 Agenda for Sustainable Development emphasizes \u0026lsquo;Vision for Everyone\u0026rsquo; and advocates for person-centered integrated eye care, including preventable blindness and vision impairment\u003csup\u003e\u003cspan citationid=\"CR13\" class=\"CitationRef\"\u003e13\u003c/span\u003e\u003c/sup\u003e. Additionally, the World Health Organization\u0026rsquo;s 2030 Global Eye Care Targets report also emphasizes the importance of preventable blindness and vision impairment by outlining two key goals: increasing effective cataract surgery coverage (eCSC) by 30% and eREC by 40%\u003csup\u003e2\u003c/sup\u003e. In response to these declarations, governments and relevant organizations have strongly supported the development of public health policies through regular vision screenings in schools and communities, improved eye care services, and heightened public awareness of prevention and timely intervention have significantly enhanced the basic healthcare environment for individuals with RD. These efforts may explain why, despite the global increase in prevalence from 1990 to 2021, the ASPR and ASYR of RD have declined, with a corresponding decrease in the AAPC.\u003c/p\u003e \u003cp\u003eOur findings are consistent with previous reports analyzing GBD data from 1990 to 2019\u003csup\u003e14\u003c/sup\u003e. Our study found that females are more susceptible to refraction disorders than males, particularly in low SDI regions and among individuals aged 50 and above. In high SDI regions, no significant gender disparity was observed, indicating that such inequality is influenced by socioeconomic development levels and age\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e, \u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e. Notably, gender inequality in the global burden of refraction disorders has persisted over the past few decades\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e, and limiting gender disparities is a crucial component of achieving the United Nations Sustainable Development Goals\u003csup\u003e\u003cspan citationid=\"CR25\" class=\"CitationRef\"\u003e25\u003c/span\u003e\u003c/sup\u003e, necessitating the formulation of gender-sensitive health policies\u003csup\u003e\u003cspan citationid=\"CR24\" class=\"CitationRef\"\u003e24\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eThe disease burden among the elderly population should not be ignored and deserves attention. Studies show that 23% of the global disease burden occurs in the elderly, accounting for approximately half of the burden in high-income countries and one-fifth in low- and middle-income countries\u003csup\u003e\u003cspan citationid=\"CR26\" class=\"CitationRef\"\u003e26\u003c/span\u003e\u003c/sup\u003e. By 2050, it is predicted that 866\u0026nbsp;million people will have uncorrected presbyopia\u003csup\u003e\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e\u003c/sup\u003e. This population faces an increased risk of refraction disorders\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e, cataracts, age-related macular degeneration, glaucoma, and diabetic retinopathy. Many elderly people fail to achieve satisfactory vision even after refractive correction, suggesting the presence of multiple coexisting eye conditions in those people. However, the coverage of healthcare resources for the elderly is particularly inadequate, exacerbating insufficient social security and limiting access to eye care services, creating a vicious cycle. Therefore, enhancing the scope and quality of eye care services is essential for reducing the global burden of vision impairment among the elderly\u003csup\u003e\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e\u003c/sup\u003e.\u003c/p\u003e \u003cp\u003eOverall, regions with lower socioeconomic status bear a heavier disease burden. However, studies have shown that patients with presbyopia in some developed countries can access appropriate optical corrections\u003csup\u003e\u003cspan citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u003c/sup\u003e. In low SDI regions, the disease burden is constrained by economic limitations and, to some extent, linked to education levels\u003csup\u003e\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e\u003c/sup\u003e. Insufficient awareness of the disease, coupled with a lack of local public health resources and financial constraints, makes it difficult for individuals to afford glasses or refractive correction surgeries. Nevertheless, it is encouraging that the global health inequality concentration index has declined from 1990 to 2021, indicating a relative reduction in disparities between countries and regions.\u003c/p\u003e \u003cp\u003eHowever, the COVID-19 pandemic, which has spread globally, has threatened human health and safety. It has not only disrupted basic healthcare services but also altered public lifestyles. The demand for near-distance work activities has increased, and the use of electronic devices has significantly risen\u003csup\u003e\u003cspan citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e, \u003cspan citationid=\"CR30\" class=\"CitationRef\"\u003e30\u003c/span\u003e\u003c/sup\u003e, while outdoor time has decreased. These factors have further contributed to the rising prevalence of RD\u003csup\u003e\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e\u003c/sup\u003e. Therefore, it is crucial to recognize the impact of COVID-19 on the health, social, and economic conditions of individuals with vision impairment. Moving forward, implementing eye health strategies tailored to different populations, regions, and genders, expanding community and school screening coverage, increasing financial investment in eye health initiatives, and enhancing access to comprehensive eye care services are essential steps to take effective action toward achieving the UNSDG.\u003c/p\u003e \u003cdiv id=\"Sec13\" class=\"Section2\"\u003e \u003ch2\u003eLimitations\u003c/h2\u003e \u003cp\u003eOur study has several limitations. First, although the GBD 2021 database provides comprehensive retrospective data, significant variations in healthcare standards and research methodologies across regions may introduce bias, potentially affecting the accuracy of the data. Therefore, further optimization of data quality is necessary. Second, clinical methods for measuring vision have evolved, particularly before the 21st century, when measurement techniques were less standardized. This may result in inaccuracies in the disease burden data of RD over the past 30 years. Additionally, differences in measurement methods across countries and regions could lead to discrepancies between years and areas. Thus, future research should aim to establish standardized and consistent vision measurement methods globally. Furthermore, a patient may simultaneously have multiple eye diseases, such as cataracts combined with presbyopia, myopia combined with high myopia fundus lesions, etc., which increases the difficulty in diagnosing the main causes of visual impairment and blindness. Another limitation is that the COVID-19 pandemic has significantly altered lifestyles and healthcare-seeking behaviors worldwide, potentially impacting the accuracy of the 2021 disease burden data. This may cause bias in our predictions. In light of these issues, future research should focus on prospective studies to enhance the rigor and reliability of findings, thereby better exploring the epidemiological characteristics of RD globally. Additionally, more specific eye conditions should be considered to accurately describe the burden of refraction disorders across different age groups.\u003c/p\u003e \u003c/div\u003e"},{"header":"Conclusion","content":"\u003cp\u003eBy conducting subgroup analyses of prevalence and YLDs across different age groups, genders, regions, countries, and SDI levels, this study provides a comprehensive and detailed analysis of the global burden of RD from 1990 to 2021. Using the BAPC model, we further predicted the global disease burden during 2022\u0026thinsp;~\u0026thinsp;2035. Our findings indicate that the global burden of RD has improved over the past 30 years. However, the increasing prevalence due to global population growth and aging underscores that RD remains a significant public health challenge that cannot be ignored. Moreover, substantial disparities persist across age groups, genders, GBD regions, countries, and SDI levels. Therefore, targeted interventions and high-quality services are needed for those subgroups. In summary, our results highlight the burden of RD across different populations and regions, aiming to raise public awareness of this issue. Our study aims to support future disease screening and policy-making, with the hope of further reducing the global burden.\u003c/p\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAuthor contributions\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eTT designed the study and searched the data. YC, YD, WQ and YY collated the data. TT, YC, and YD performed analysis and wrote the manuscript. QZ reviewed the statistical analysis and manuscript. All authors reviewed and agreed on the final version of the manuscript. \u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgments\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eWe thank all the participants and staff for their dedication and contributions. We thank Bullet Edits Limited for the linguistic editing and proofreading of the manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eData availability statement\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll the data of our study is available from https://vizhub.healthdata.org/gbd-results/.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eEthical Approval\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNot applicable.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eNo funding.\u0026nbsp;\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eConflict of interest statement\u0026nbsp;\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare no competing financial interests.\u0026nbsp;\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n\u003cli\u003eSchiefer U, Kraus C, Baumbach P, et al. Refractive errors[J]. 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The economics of vision impairment and its leading causes: A systematic review[J]. EClinicalMedicine, 2022, 101354, doi:10.1016/j.eclinm.2022.101354.\u003c/li\u003e\n\u003cli\u003eGBD 2019 Blindness and Vision Impairment Collaborator,Vision Loss Expert Group of the Global Burden of Disease Study. Trends in prevalence of blindness and distance and near vision impairment over 30 years: an analysis for the Global Burden of Disease Study[J]. Lancet Glob Health, 2021, 2: e130-e143, doi:10.1016/s2214-109x(20)30425-3.\u003c/li\u003e\n\u003cli\u003eFlaxman SR, Bourne RRA, Resnikoff S, et al. Global causes of blindness and distance vision impairment 1990-2020: a systematic review and meta-analysis[J]. Lancet Glob Health, 2017, 12: e1221-e1234, doi:10.1016/s2214-109x(17)30393-5.\u003c/li\u003e\n\u003cli\u003eJonas JB, Ang M, Cho P, et al. IMI Prevention of Myopia and Its Progression[J]. Invest Ophthalmol Vis Sci, 2021, 5: 6, doi:10.1167/iovs.62.5.6.\u003c/li\u003e\n\u003cli\u003eUnited Nations. General Assembly (75th sess. : 2020-2021). Vision for everyone : accelerating action to achieve the Sustainable Development Goals : resolution / adopted by the General Assembly. 2021. https://digitallibrary.un.org/record/3933853?v=pdf#files.\u003c/li\u003e\n\u003cli\u003eLi HY, Liu YM, Dong L, et al. Global, regional, and national prevalence, disability adjusted life years, and time trends for refraction disorders, 1990-2019: findings from the global burden of disease study 2019[J]. BMC Public Health, 2021, 1: 1619, doi:10.1186/s12889-021-11648-1.\u003c/li\u003e\n\u003cli\u003eYao Q, Jiang B, Wu J, et al. The Trends in Prevalence of Blindness Caused by Refraction Disorders in China from 1990 to 2019 and Its Predictions: Findings from the Global Burden of Disease Study 2019[J]. Ophthalmic Epidemiol, 2024, 1-8, doi:10.1080/09286586.2024.2407900.\u003c/li\u003e\n\u003cli\u003eBourne RRA, Cicinelli MV, Sedighi T, et al. Effective refractive error coverage in adults aged 50 years and older: estimates from population-based surveys in 61 countries[J]. Lancet Glob Health, 2022, 12: e1754-e1763, doi:10.1016/s2214-109x(22)00433-8.\u003c/li\u003e\n\u003cli\u003eDi Renzo L, Gualtieri P, Pivari F, et al. Eating habits and lifestyle changes during COVID-19 lockdown: an Italian survey[J]. J Transl Med, 2020, 1: 229, doi:10.1186/s12967-020-02399-5.\u003c/li\u003e\n\u003cli\u003eZhang XJ, Zhang Y, Kam KW, et al. Prevalence of Myopia in Children Before, During, and After COVID-19 Restrictions in Hong Kong[J]. JAMA Netw Open, 2023, 3: e234080, doi:10.1001/jamanetworkopen.2023.4080.\u003c/li\u003e\n\u003cli\u003eWang J, Li Y, Musch DC, et al. Progression of Myopia in School-Aged Children After COVID-19 Home Confinement[J]. JAMA Ophthalmol, 2021, 3: 293-300, doi:10.1001/jamaophthalmol.2020.6239.\u003c/li\u003e\n\u003cli\u003eEnthoven CA, Polling JR, Verzijden T, et al. Smartphone Use Associated with Refractive Error in Teenagers: The Myopia App Study[J]. Ophthalmology, 2021, 12: 1681-1688, doi:10.1016/j.ophtha.2021.06.016.\u003c/li\u003e\n\u003cli\u003eGBD 2021 Demographics Collaborators. Global age-sex-specific mortality, life expectancy, and population estimates in 204 countries and territories and 811 subnational locations, 1950-2021, and the impact of the COVID-19 pandemic: a comprehensive demographic analysis for the Global Burden of Disease Study 2021[J]. Lancet, 2024, 10440: 1989-2056, doi:10.1016/s0140-6736(24)00476-8.\u003c/li\u003e\n\u003cli\u003eGBD 2021 Diseases and Injuries Collaborators. Global incidence, prevalence, years lived with disability (YLDs), disability-adjusted life-years (DALYs), and healthy life expectancy (HALE) for 371 diseases and injuries in 204 countries and territories and 811 subnational locations, 1990-2021: a systematic analysis for the Global Burden of Disease Study 2021[J]. Lancet, 2024, 10440: 2133-2161, doi:10.1016/s0140-6736(24)00757-8.\u003c/li\u003e\n\u003cli\u003eLiu L, Jiao J, Yang X, et al. Global, Regional, and National Burdens of Blindness and Vision Loss in Children and Adolescents from 1990 to 2019: A Trend Analysis[J]. Ophthalmology, 2023, 6: 575-587, doi:10.1016/j.ophtha.2023.02.002.\u003c/li\u003e\n\u003cli\u003eLou L, Liu X, Tang X, et al. Gender Inequality in Global Burden of Uncorrected Refractive Error[J]. Am J Ophthalmol, 2019, 1-7, doi:10.1016/j.ajo.2018.09.020.\u003c/li\u003e\n\u003cli\u003eHeise L, Greene ME, Opper N, et al. Gender inequality and restrictive gender norms: framing the challenges to health[J]. Lancet, 2019, 10189: 2440-2454, doi:10.1016/s0140-6736(19)30652-x.\u003c/li\u003e\n\u003cli\u003ePrince MJ, Wu F, Guo Y, et al. The burden of disease in older people and implications for health policy and practice[J]. Lancet, 2015, 9967: 549-62, doi:10.1016/s0140-6736(14)61347-7.\u003c/li\u003e\n\u003cli\u003eHashemi A, Khabazkhoob M,Hashemi H. High prevalence of refractive errors in an elderly population; a public health issue[J]. BMC Ophthalmol, 2023, 1: 38, doi:10.1186/s12886-023-02791-x.\u003c/li\u003e\n\u003cli\u003eYin J, Jiang B, Zhao T, et al. Trends in the global burden of vision loss among the older adults from 1990 to 2019[J]. Front Public Health, 2024, 1324141, doi:10.3389/fpubh.2024.1324141.\u003c/li\u003e\n\u003cli\u003eFricke TR, Tahhan N, Resnikoff S, et al. Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia: Systematic Review, Meta-analysis, and Modelling[J]. Ophthalmology, 2018, 10: 1492-1499, doi:10.1016/j.ophtha.2018.04.013.\u003c/li\u003e\n\u003cli\u003eBaird PN, Saw SM, Lanca C, et al. Myopia[J]. Nat Rev Dis Primers, 2020, 1: 99, doi:10.1038/s41572-020-00231-4.\u003c/li\u003e\n\u003c/ol\u003e"},{"header":"Table","content":"\u003cp\u003eTable 1 is available in the Supplementary Files section.\u003c/p\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":true,"highlight":"","institution":"","isAcceptedByJournal":false,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":false,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true},"keywords":"Refraction disorders, GBD 2021, Prevalence, Years lived with disability","lastPublishedDoi":"10.21203/rs.3.rs-6172901/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-6172901/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003e\u003cb\u003ePurpose\u003c/b\u003e\u003c/p\u003e \u003cp\u003eTo estimate the global, regional, and national burden of vision impairment due to refraction disorders (RD) from 1990 to 2021 based on sex, age, and Socio-demographic Index (SDI), and to predict future disease trends.\u003c/p\u003e\u003cp\u003e\u003cb\u003eMethods\u003c/b\u003e\u003c/p\u003e \u003cp\u003eThis retrospective demographic analysis utilized data from the 2021 Global Burden of Disease (GBD) database. Prevalence, years lived with disability (YLDs), age-standardized prevalence rates (ASPR), and age-standardized YLDs rates (ASYR) of RD from 1990 to 2021 were analyzed to assess temporal, age, and sex-specific trends. We calculated the Average Annual Percentage Change (AAPC) to determine changes in prevalence and YLDs and used the Bayesian Age-Period-Cohort (BAPC) model to forecast the disease burden of RD from 2020 to 2035.\u003c/p\u003e\u003cp\u003e\u003cb\u003eResults\u003c/b\u003e\u003c/p\u003e \u003cp\u003eASPR and ASYR declined from 1990 to 2021, the AAPC is -3.76 (95% confidence interval [CI]: -4.20~-3.32) and \u0026minus;\u0026thinsp;0.26 (95% CI: -0.28~-0.25), respectively. In 2021, the global prevalence RD was 159,765,917 (95% uncertainty interval [UI]: 142,526,915\u0026thinsp;~\u0026thinsp;178,698,348). The prevalence was slightly higher in females than in males, with a higher disease burden among middle-aged and elderly populations. There is a slight negative correlation in regional ASPR (r\u0026asymp;-0.32, \u003cem\u003eP\u003c/em\u003e\u0026thinsp;\u0026lt;\u0026thinsp;0.001), with South Asia exhibiting the highest ASPR (3,398/100,000 people [95% UI: 2992\u0026thinsp;~\u0026thinsp;3860]). The global prevalence of RD is predicted to increase, while the ASPR is expected to decrease from 2022 to 2035.\u003c/p\u003e\u003cp\u003e\u003cb\u003eConclusion\u003c/b\u003e\u003c/p\u003e \u003cp\u003eGlobal prevalence of RD has increased in the past 30 years and is predicted to continue increasing over the next 15 years. There was a heavier burden among females, middle-aged, and elderly populations.\u003c/p\u003e","manuscriptTitle":"Trend Analysis of Global, Regional, and National Burdens of Visual Impairment Due to Refraction Disorders from 1990 to 2021: Findings from the Global Burden of Disease Study 2021","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2025-04-26 15:59:33","doi":"10.21203/rs.3.rs-6172901/v1","editorialEvents":[{"type":"communityComments","content":0}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"researchsquare","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":true,"externalIdentity":"","sideBox":"","snPcode":"","submissionUrl":"/submission","title":"Research Square","twitterHandle":"researchsquare","acdcEnabled":true,"dfaEnabled":false,"editorialSystem":"","reportingPortfolio":"","inReviewEnabled":false,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"fbfa1502-e6fe-4305-ab5a-d946ceee4050","owner":[],"postedDate":"April 26th, 2025","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"posted","subjectAreas":[{"id":47484945,"name":"Health sciences/Medical research/Epidemiology"},{"id":47484946,"name":"Health sciences/Diseases/Eye diseases/Refractive errors"},{"id":47484947,"name":"Health sciences/Health care/Public health/Epidemiology"}],"tags":[],"updatedAt":"2025-10-29T08:45:56+00:00","versionOfRecord":[],"versionCreatedAt":"2025-04-26 15:59:33","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-6172901","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-6172901","identity":"rs-6172901","version":["v1"]},"buildId":"8U1c8b4HqxoKbykW_rLl7","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}