Glaucoma is a neurodegenerative eye disease and a leading cause of irreversible blindness worldwide. It is marked by the degeneration of the optic nerve and the loss of retinal ganglion cells, which leads to significant visual field loss (1). The development and severity of glaucoma largely depend on the optic nerve’s ability to withstand pressure-induced damage (2). Beyond directly affecting vision, glaucoma imposes significant lifestyle restrictions on patients, increasing the risks of falls and driving difficulties. Along with treatment costs, it imposes substantial psychological and economic burdens on patients and their families (2). The impact of glaucoma is particularly severe in middle-aged and older adults, as the risk of developing the disease significantly increases with age (3, 4). The global trend towards an aging population highlights this issue, especially in high-income and rapidly developing countries (5).

Recent studies have shown that the prevalence of glaucoma in the older adults can be as high as 3.5%, a rate that increases with age. This affects individuals’ quality of life, particularly in vision-critical daily activities and social interactions, and also exacerbates the social and economic burden (6).

The Global Burden of Disease (GBD) Collaborative Network initiated the GBD study, which assesses 288 causes of death, 371 diseases and injuries, and 88 risk factors across 204 countries and regions (7). This study on disease burden serves as a crucial foundation for the development and implementation of health policies. Consequently, countries worldwide have been analyzing disease burden to make informed, scientifically-based health decisions.

The GBD 2021 study stands as the most detailed and authoritative resource for assessing the global impact of all diseases and injuries, providing insights into health deterioration trends and levels worldwide. This pivotal tool measures life loss due to preventable conditions and, for the first time, quantifies health impacts attributable to the COVID-19 pandemic (7). The burden of glaucoma is strongly associated with socio-economic status, age, gender, and various other factors. According to the 2019 World Health Organization (WHO) Vision Report, 76 million people aged 40–80 globally were projected to have glaucoma in 2020, up from 69.2 million in 2016, with the number expected to reach 95.4 million by 2030. However, with changes in lifestyles and increased life expectancy, the incidence pattern of glaucoma has also changed. Following the COVID-19 pandemic, there remains a significant gap in global burden reports on glaucoma based on the latest GBD study. Focusing on the middle-aged and older population is particularly critical, as these groups face a higher risk of glaucoma, which is further exacerbated by aging populations globally. By honing in on individuals aged 45 and older, this research seeks to uncover specific risk factors and trends that can inform more effective prevention and management strategies tailored to this vulnerable group, ultimately contributing to better health outcomes and reduced disparities in eye health care.

This article describes the latest epidemiology of glaucoma after the COVID-19 pandemic. It analyzes the prevalence and Disability-Adjusted Life Years (DALYs) of glaucoma globally, regionally, and nationally from 1990 to 2021, and provides predictions for the future of glaucoma.

In this study, we quantified the prevalence and DALYs of glaucoma using age-standardized rates (ASR) and their 95% UI. The predicted values per 100,000 population, including their 95% UI, were calculated using the world standard population. Age-standardized DALY rates (ASDRs) were calculated using the world standard population as a reference. Specifically, DALY rates for each age group were weighted according to the corresponding proportion in the world standard population, and then summed across all age groups to obtain an internationally comparable rate. We employed the Joinpoint regression analysis model to assess the temporal trends in age-standardized prevalence rates (ASPR) and age-standardized DALYs (ASDR) of glaucoma globally and regionally. This model is commonly used in epidemiological research to identify and characterize significant change points in time series data across global and national scales. We conducted a detailed analysis of the ASPR and ASDR for the years 1990 and 2021. To evaluate the overall trends during this period, we calculated the average annual percentage change (AAPC). An AAPC with a lower limit of the 95% confidence interval (CI) exceeding zero indicates an increasing trend, whereas an AAPC with the upper limit of the 95% UI below zero suggests a decreasing trend. When the 95% UI of the AAPC includes zero, it indicates a stable trend. We elucidate the burden of glaucoma across gender, age groups (spanning every 5 years from 45 to 95+), and SDI. Moreover, we examine the global impact of glaucoma on a national scale and analyze the correlation between socio-demographic status and DALY, using the SDI as a framework.

Moreover, we plotted dual Y-axis graphs for 2021 that report the number and age-standardized prevalence and DALY rates by gender, age, and SDI regions, as well as graphs illustrating the relationship between SDI and changes across countries.

To provide information for policies, planning, and practices aimed at achieving universal health coverage and reducing health inequalities, we used the Slope Index of Inequality (SII) and Concentration Index (CI) to analyze absolute and relative health inequalities in glaucoma (11). The SII was calculated by regressing each country’s DALYs on the SDI-related relative position scale, defined by the midpoint of the cumulative population range of SDI rankings. The CI was determined by calculating the ratio of the area between the Lorenz curve and the diagonal, using cumulative SDI rankings and cumulative DALY fractions. This study also predicted global prevalence and DALYs for 2040 to assess the future GBD of glaucoma. The model was implemented using the NORDPRED package in R. All statistical analyses and visualizations were conducted using R software, with p < 0.05 considered statistically significant (12).

We utilized frontier analysis to further assess the relationship between the burden of glaucoma and socio-demographic development. To create a nonlinear boundary representing the minimum achievable burden based on the level of development, we employed non-parametric Data Envelopment Analysis (DEA), as described in prior studies. The distance between a country’s observed DALY rate and this boundary is termed the efficiency gap, indicating the unrealized health gains relative to the country’s or region’s current development level (13, 14).

In this study, we selected two outcome indicators—prevalence and DALYs—to analyze glaucoma burden trends over the past 32 years across 204 countries and regions. Compared with GBD 2019, the GBD 2021 study incorporated additional research and expanded data sources, providing the most up-to-date estimates of glaucoma epidemiology and enhancing data reliability. Over this period, the global numbers of prevalence and DALYs increased by 86.24 and 62.51%, respectively. However, the AAPC for ASPR and ASDR was negative globally and across all 21 GBD regions, indicating an overall declining trend. Despite rising absolute case numbers driven by population growth and aging, advances in diagnostic techniques and treatment have substantially improved disease management. For example, the adoption of optical coherence tomography (OCT) has enabled earlier detection and intervention, while newer intraocular pressure–lowering medications and minimally invasive surgeries have enhanced disease control. Global health initiatives, such as the WHO “Vision 2020” project, have also expanded access to eye care services in low- and middle-income countries, contributing to the global decline in prevalence and ASDR (15, 16).

The COVID-19 pandemic, however, posed short-term challenges. Routine eye examinations were often postponed, and access to diagnostic tests and surgical treatments was disrupted, leading to delayed diagnoses and disease progression. Medication supply chain interruptions further affected management. Although our results suggest that the long-term global trend in glaucoma burden remains downward, the pandemic likely exacerbated disparities, particularly in low-resource settings where healthcare systems were already fragile. Continued monitoring of its long-term impact is necessary to ensure continuity of glaucoma care during future global health crises (17).

Regional differences remain striking. In the 2021 GBD study, the highest ASPR of glaucoma was observed in Oceania, Central Europe, high-income North America, and sub-Saharan Africa, while the lowest occurred in Central Latin America, North Africa and the Middle East, and South Asia. The highest ASDR was recorded in Western and Eastern sub-Saharan Africa, exceeding 100 cases per 100,000 population, whereas Southern Latin America and Southeast Asia reported the lowest levels. These disparities reflect the interplay of socioeconomic, healthcare, and biological factors. High-income countries benefit from strong healthcare systems, advanced diagnostics, and wider access to treatment, resulting in lower disease burden. In contrast, low- and middle-income countries face limited infrastructure, shortages of ophthalmologists, delayed diagnosis, and financial barriers, leading to higher burden. Additionally, biological factors such as thinner corneal thickness and structural variations in the trabecular meshwork contribute to the higher prevalence of primary open-angle glaucoma (POAG) in African populations, reinforcing the need for targeted interventions in sub-Saharan Africa (18–22).

Sex and age also influence disease burden. We observed that in males, glaucoma prevalence and DALYs peaked at ages 70–74, while in females, prevalence peaked at the same age but DALYs peaked later, at 80–84 years. This pattern may reflect earlier onset of severe impairment in men due to lifestyle factors such as smoking and alcohol use, whereas women experience slower progression but greater cumulative burden because of longer life expectancy and reduced estrogen protection after menopause. These differences highlight the importance of gender- and age-specific prevention and management strategies (23–26).

Our study further demonstrated that ASDR negatively correlates with SDI at both regional and national levels, underscoring the role of socioeconomic factors in shaping glaucoma burden. Although absolute inequalities in glaucoma burden have declined in recent decades, relative inequalities remain largely unchanged. Low- and middle-income countries continue to face disproportionate challenges due to weaker health systems, fewer trained specialists, and the economic impact of vision loss, which reduces labor productivity and perpetuates poverty. Addressing these issues requires strengthening health system capacity, improving access to affordable care, and expanding international cooperation, particularly in Africa and South Asia (27–29).

Frontier analysis revealed that countries at different development levels continue to exhibit considerable efficiency gaps, with many performing below the achievable minimum burden relative to their SDI. Encouragingly, some low-SDI countries achieve leading outcomes despite resource constraints, serving as models for optimizing glaucoma care in similar contexts. Life expectancy also plays a role in shaping glaucoma burden: populations with longer lifespans face greater cumulative risk and longer disease progression, leading to higher DALY rates, whereas shorter life expectancy may limit exposure to glaucoma but reflects broader health system weaknesses. Moreover, the high prevalence of normal-tension glaucoma in countries such as Japan and South Korea underscores the importance of genetic, environmental, and healthcare-seeking differences that shape national-level burdens (30–34).

Future research should prioritize longitudinal cohort studies to evaluate glaucoma progression under different socioeconomic contexts, as well as subtype-specific analyses (e.g., open-angle, angle-closure, and normal-tension glaucoma) to inform targeted strategies. Incorporating real-world data from electronic health records and population-based surveys could refine burden estimates, while continued evaluation of the long-term effects of global disruptions such as COVID-19 remains essential. These directions will strengthen the evidence base for developing tailored interventions and guiding equitable resource allocation.

Finally, despite persistent challenges, projections suggest that global glaucoma prevalence and age-standardized DALY rates will continue to decline until 2040. This encouraging trend reflects progress in prevention and management, supporting the wider adoption of effective measures worldwide. Nonetheless, caution is warranted in interpreting results, as limitations of the GBD database remain, including possible misclassification, lack of subtype-specific data, and regional variability in data quality. Future studies should address these gaps with more rigorous methodologies to ensure reliable and actionable evidence.

This study utilizes data from the 2021 GBD Study to offer a comprehensive analysis of the burden of glaucoma at global, regional, and national levels. The findings indicate that, although the prevalence and DALY associated with glaucoma have increased worldwide over the past few decades, both metrics are projected to decline from 2021 to 2040. This encouraging trend may be attributed to the gradual improvement in glaucoma prevention and management strategies globally.

The study also reveals significant regional disparities, particularly in areas with a low SDI, where the health burden of glaucoma remains high. This uneven distribution highlights both challenges and opportunities for optimizing health outcomes in resource-limited settings. The findings emphasize the need for global health policymakers to consider regional inequalities in the glaucoma burden when developing control strategies and allocating resources. Future research should focus on analyzing countries that have achieved notable success in glaucoma prevention and treatment to identify and disseminate effective practices and policies.

Conversely, in countries where glaucoma management is less successful, in-depth analysis is required to uncover the root causes of these challenges and to develop tailored support and improvement strategies. By systematically analyzing these issues and sharing successful strategies, the global health community can more effectively work towards reducing the burden of glaucoma worldwide.