# Global estimates on the number of people blind or visually impaired by diabetic retinopathy: a meta-analysis from 2000 to 2020

Katie Curran, Tunde Peto, Jost Jonas, David Friedman, Judy Kim, Janet

Leasher, Ian Tapply, Arthur Fernandes, Maria Vittoria Cicinelli, Alessandro

Arrigo, et al.

► To cite this version:

Katie Curran, Tunde Peto, Jost Jonas, David Friedman, Judy Kim, et al.. Global estimates on the number of people blind or visually impaired by diabetic retinopathy: a meta-analysis from 2000 to 2020. Eye, 2024, 38 (11), pp.2047-2057. 10.1038/s41433-024-03101-5 . hal-05019321

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# Global estimates on the number of people blind or visually impaired by diabetic retinopathy: a meta-analysis from 2000 to 2020

Vision Loss Expert Group of the Global Burden of Disease Study* and the GBD 2019 Blindness and Vision Impairment Collaborators*

© The Author(s) 2024

**OBJECTIVES:** To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by diabetic retinopathy and their proportion of the total number of vision-impaired individuals.

**METHODS:** Data from population-based studies on eye diseases between 1980 to 2018 were compiled. Meta-regression models were performed to estimate the prevalence of blindness (presenting visual acuity <3/60) and moderate or severe vision impairment (MSVI; <6/18 to ≥3/60) attributed to DR. The estimates, with 95% uncertainty intervals [UIs], were stratified by age, sex, year, and region.

**RESULTS:** In 2020, 1.07 million (95% UI: 0.76, 1.51) people were blind due to DR, with nearly 3.28 million (95% UI: 2.41, 4.34) experiencing MSVI. The GBD super-regions with the highest percentage of all DR-related blindness and MSVI were Latin America and the Caribbean (6.95% [95% UI: 5.08, 9.51]) and North Africa and the Middle East (2.12% [95% UI: 1.55, 2.79]), respectively. Between 2000 and 2020, changes in DR-related blindness and MSVI were greater among females than males, predominantly in the super-regions of South Asia (blindness) and Southeast Asia, East Asia, and Oceania (MSVI).

**CONCLUSIONS:** Given the rapid global rise in diabetes and increased life expectancy, DR is anticipated to persist as a significant public health challenge. The findings emphasise the need for gender-specific interventions and region-specific DR healthcare policies to mitigate disparities and prevent avoidable blindness. This study contributes to the expanding body of literature on the burden of DR, highlighting the need for increased global attention and investment in this research area.

Eye (2024) 38:2047–2057; https://doi.org/10.1038/s41433-024-03101-5

## INTRODUCTION

Diabetes mellitus (DM) and its complications are a major burden of disease around the world. DM has increased significantly in recent decades and will continue to rise in the next few decades, with a greater burden expected in low-middle income countries (LMICs) [1]. One of the most common microvascular complications of DM is diabetic retinopathy (DR). According to previous large-population based studies and meta-analyses, DR has been recognized as one of the most common causes of blindness and vision impairment among the working-age population; however, this is not true for some countries, such as the United Kingdom, due to the implementation of national DR strategies aimed at identifying and treating patients with this condition [2–9]. The Global Burden of Disease Study (GBD) began 30 years ago to systematically assess and scientifically report on critical health outcomes including DM and its complications. The findings are reported longitudinally and across various populations [10]. In 2020, DR was listed as one of the leading causes of global blindness among those aged 50 years and above [3]. Leasher et al. assessed changes in the prevalence of DR-related blindness and moderate or severe vision impairment (MSVI) from 1990 to 2010 [8]. Findings showed that DR accounted for 2.6% of all blindness and 1.9% of all MSVI in 2010, an increase from 2.1% and 1.3%,

respectively, from 1990 [8]. Early detection and treatment interventions for DR can reduce the risk of severe visual loss by approximately 90% [11].

The Lancet Global Health Commission emphasised how improving eye health contributes to achieving the sustainable development goals (SDGs) of improving general health and well-being, reducing poverty and increasing work productivity, and improving education and equity [7]. Due to the unmet need of an ageing and growing population globally, eye health is a major public health concern that requires urgent attention to develop innovative treatments and deliver services on a large scale. Political commitment is necessary to act on eye health, particularly in low-resource settings [7, 12].

The current meta-analysis provides an update of all available population-based studies from 2000 to 2020 to present estimates on the number of people (aged 50 years+) affected by DR-related blindness and DR-related MSVI. Additionally, we investigate the global and regional differences in the prevalence of DR-related blindness and MSVI, and differences by sex.

## MATERIALS/SUBJECTS AND METHODS

Preparation of data included first a systematic review of published (between Jan 1, 1980, and Oct 1, 2018) population-based studies

<footnote>*Lists of authors and their affiliations appear at the end of the paper.</footnote>
of vision impairment and blindness by the Vision Loss and Expert Group (VLEG) that also included gray literature sources. Eligible studies from this review were then combined with data from Rapid Assessment of Avoidable Blindness (RAAB) studies. Data from the US National Health and Nutrition Examination survey and the World Health Organization (WHO) Study on Global Ageing and Adult Health were contributed by the GBD team. More detailed methods are published elsewhere [3, 13] and briefly discussed as follows.

In total, VLEG identified 137 studies and extracted data from 70 studies in their 2010 review, and additional 67 studies in their 2014–18 review. Studies were primarily national and subnational cross-sectional surveys. Additionally, the VLEG commissioned the preparation of 5-year age-disaggregated RAAB data from the RAAB repository. Studies were included if they met the following criteria: visual acuity data had to be measured using a test chart that could be mapped to the Snellen scale, and the sample had to be representative of the population. Self-report of vision loss was excluded. We used International Classification of Diseases 11th (ICD-11) edition criteria for vision impairment, as used by WHO, which categorises people according to vision in the better eye on presentation, in which moderate vision impairment is defined as a visual acuity of 6/60 or better but less than 6/18, severe vision impairment as a visual acuity of 3/60 or better but less than 6/60, and blindness as a visual acuity of less than 3/60 or less than 10° visual field around central fixation (although the visual field definition is rarely used in population-based eye surveys) [14].

First, we separated raw data into vision-loss envelopes for all-cause mild, moderate, and severe vision impairment, and blindness. Data were input into a mixed-effects meta-regression tool developed by the Institute for Health Metrics and Evaluation (IHME) called MR-BRT (meta regression; Bayesian; regularized; trimmed) [15]. Presenting vision impairment was the reference definition for each level of severity. Undercorrected refractive error data were extracted directly from data sources where available, and otherwise calculated by subtracting best-corrected vision impairment from presenting vision impairment prevalence for each level of severity in studies that reported both measures for a given location, sex, age group, and year. All other causes were quantified as part of the best-corrected estimates of vision impairment at each level of severity.

We modeled distance vision impairment and blindness due to the following causes: cataract, undercorrected refractive error, age-related macular degeneration, myopic macular degeneration, glaucoma, diabetic retinopathy, and other causes of vision impairment (in aggregate). Minimum age for inclusion of data for these causes was set at 20 years for cataract and diabetic retinopathy, and 45 years for glaucoma and age-related macular degeneration. Other vision impairment estimates were combined with less prevalent causes of vision impairment to create a residual category (e.g., retinopathy of prematurity, corneal opacities or optic atrophy, trachoma).

We produced location, year, age, and sex-specific estimates of MSVI and blindness using Disease Modeling Meta-Regression (Dismod-MR) 2.1 [16]. The data processing steps are described elsewhere [3]. Briefly, Dismod-MR 2.1 models were run for all vision impairment by severity (moderate, severe, blindness) regardless of cause and, separately, for MSVI and blindness due to each modeled cause of vision impairment (e.g., MSVI due to cataract and blindness due to cataract). Then, models of MSVI due to specific causes were split into moderate and severe estimates using the ratio of overall prevalence in the all-cause moderate presenting vision impairment and severe presenting vision impairment models. Next, prevalence estimates for all causes by severity were scaled to the models of all-cause prevalence by severity. This produced final estimates by age, sex, year, and location for each individual cause of vision impairment by

severity. We age-standardized our estimates using the GBD standard population [17].

## RESULTS

According to our estimates from 2020, approximately 1.07 million (95% uncertainty intervals (UIs): 0.76, 1.51) people were blind and nearly 3.28 million (95% UI: 2.41, 4.34) had MSVI globally due to DR (Table 1). An estimated 462,000 males and 611,000 females of all ages, and 368,000 males and 494,000 females aged ≥50 years had DR-related blindness in 2020 (Table 2). The number of males and females (all ages) with DR-related MSVI in 2020 was 1.4 million and 1.8 million, respectively, whereas an estimated 1.3 million and 1.7 million people were aged 50 years and over (Table 3). Higher prevalence rates of DR-related blindness were seen among females aged 60 years and above, with the highest rates observed in people aged >95 years. Higher prevalence rates of DR-related blindness and MSVI were seen among females aged 60 years and above, with the highest rates observed in females aged >95 years.

DR caused 2.50% (95% UI: 1.77, 3.52) of blindness in 2020 worldwide. Regionally, the highest percentage of all DR-related blindness was found in Latin America and Caribbean (6.95% [95% UI: 5.08, 9.51]) and High-Income super-regions (5.37% [95% UI: 3.86, 7.55]) (Table 1). The super-regions with the lowest percentage of all DR-related blindness were Central Europe, Eastern Europe, and Central Asia (0.97% [95% UI: 0.67, 1.39]), and Sub-Saharan Africa (0.98% [95% UI: 0.69, 1.40]). DR caused 1.11% (95% UI: 0.82, 1.47) of MSVI in 2020 worldwide. North Africa and Middle East (2.12% [95% UI: 1.55, 2.79]), and Latin America and Caribbean (1.84% [95% UI: 1.36, 2.45]) were super-regions with the highest percentage of all MSVI due to DR (Table 1).

In 2020, the global age-standardized prevalence of DR-related blindness in those aged ≥50 years was 0.05% (95% UI: 0.03, 0.07) and 0.16% (95% UI: 0.12, 0.21) for DR-related MSVI (Table 1). The super-region with the highest age-standardized prevalence of DR-related blindness was Latin American and Caribbean (0.15% [95% UI: 0.10, 0.21]). The lowest age-standardized prevalence of DR-related blindness in 2020 was in Central Europe, Eastern Europe, and Central Asia (0.01% [95% UI: 0.01, 0.01]). The super-regions with the highest age-standardized prevalence of DR-related MSVI in 2020 were North Africa and Middle East (0.41% [95% UI: 0.30, 0.55]), and Latin America and the Caribbean (0.30% [95% UI: 0.22, 0.40]). The lowest estimates were found in the High-Income (0.08% [95% UI: 0.06, 0.11]) and Central Europe, Eastern Europe, and Central Asia (0.09% [95% UI: 0.07, 0.13]) super-regions (Table 1). Figure 1 presents the crude prevalence of blindness and MSVI due to DR in 2020 across super-regions.

Between 2000 and 2020, the global percentage change in age-standardized prevalence of DR-related blindness among adults (≥50 years) showed different trends for males and females (Supplementary file, Table S1). For males, there was a minimal decrease of −0.10% (95% UI: −0.54, 0.34), while females experienced an increase of +12.89% (95% UI: 12.40, 13.38). An overall increase in the age-standardized prevalence of DR-related blindness among adults aged ≥50 years (both sexes) was found in South Asia (+25.66% [95% UI: 25.07, 26.24]), Southeast Asia, East Asia and Oceania (+15.36% [95% UI: 14.80, 15.92]) and Sub-Saharan Africa (+2.47% [95% UI: 2.01, 2.94]). An increase of +14.92% (95% UI: 14.39, 15.45) in age-standardized prevalence of DR-related blindness in South Asia from 2000 to 2020 was observed for males, while females experienced even greater gains with a rise of +34.68% (95% UI: 34.04, 35.32). In Southeast Asia, East Asia, and Oceania, the increase in age-standardized prevalence of DR-related blindness from 2000 to 2020 was +3.43% (95% UI: 2.94, 3.91) for males, compared to +26.34% (95% UI: 25.72, 26.97) for females. In Sub-Saharan Africa, although the overall age-standardized prevalence of DR-related blindness
from 2000 to 2020 increased, a decrease was found among males (−12.46% [95% UI: −12.87, −12.04]) compared to females (+16.79% [95% UI: 16.27, 17.30]). All other super-regions demonstrated a decrease in the age-standardized prevalence of DR-related blindness (≥50 years) from 2000 to 2020 overall. In Central Europe, Eastern Europe and Central Asia, the age-standardized prevalence of DR-related blindness decreased by −21.99% (95% UI: −22.41, −21.58) for males compared to −3.15% (95% UI: −3.61, −2.70) for females. In Latin America and Caribbean, a decrease of −20.74% (95% UI: −21.06, −20.41) was observed in males, with a smaller decrease (−5.49% [95% UI: −5.86, −5.11]) among females. In the High-Income super-region, a reduction of −15.73% (95% UI: −16.13, −15.32) and −8.46% (95% UI: −8.83, −8.09) was found in males and females, respectively. Supplementary file contains Figs. (S1–S4) illustrating the total number of cases (males and females) with DR-related blindness and MSVI between 2000 and 2020, for all 21 GBD world regions, including the global total for comparison.

From 2000 to 2020, there was a decrease in the global percentage change in age-standardized prevalence of DR-related MSVI (≥50 years) among males (−0.93% [95% UI: −1.29, −0.56]), while females experienced an increase (+3.62% [95% UI: 3.25, 3.99]). Between 2000 and 2020, the super-region of Southeast Asia, East Asia, and Oceania showed an increase in the age-standardized prevalence of DR-related MSVI for both males (+1.17%, [95% UI: 0.79, 1.55]) and females (+3.33%, [95% UI: 2.95, 3.71]). In Sub-Saharan Africa, there was a decrease in the age-standardized prevalence of DR-related MSVI among males (−1.98%, [95% UI: −2.34, −1.63]), whereas females experienced an increase (+1.06%, [95% UI: 0.69, 1.42]). All other super-regions demonstrated a decrease in the age-standardized prevalence of DR-related MSVI (≥50 years) between 2000 and 2020 for both sexes. The super-region of North Africa and the Middle East showed the most notable decline in age-standardized DR-related MSVI for both sexes (−15.35% [−15.66, −15.05]). Among males, there was a decrease of −16.43% (95% UI: −16.73, −16.12), while females exhibited a −14.57% (95% UI: −14.88, −14.26) decrease (Supplementary file, Table S2).

The global percentage change in crude prevalence for DR-related blindness between 2000 and 2020 was +1.41% (95% UI: −0.96, 1.85) in males compared to a +13.32% (95% UI: 12.83, 13.80) increase in females, and +7.90% (95% UI: 7.43, 8.36) overall. The percentage change in crude prevalence of DR-related MSVI was also higher among females (+3.56% [95% UI: 3.18, 3.93]) compared to males (+1.31% [95% UI: 0.93, 1.69]) globally (Supplementary file, Tables S1, 2).

## DISCUSSION

Although DR remains highly prevalent, the figures from 2020 show a slight decrease compared to those reported in 2010 [8]. In 2020, DR accounted for 2.5% of global blindness and 1.1% of MSVI, down from 2.6% and 1.9%, respectively, in 2010. Leasher et al. also showed that the highest age-standardized prevalence of DR-related blindness and MSVI was in the super-regions of North Africa/Middle East, Sub-Saharan Africa, and South Asia, while the lowest prevalence was in High-Income regions [8]. An increase in the numbers of people with DR-related blindness and MSVI with a relatively unchanged age-standardized prevalence from 2010 to 2020 may be attributed to the increasing population and average age in most regions, coupled with falling death rates.

Our study found that DR-related blindness has increased more among females than males in almost all super-regions. The largest sex-related inequalities were found in South Asia, Southeast Asia, East Asia and Oceania, and Sub-Saharan Africa. Though there are age-adjusted declines in DR prevalence for some super-regions, the overall global crude prevalence of both DR-related blindness and DR-related MSVI for males, females, and overall has increased

globally due to aging and growth of the population. These figures represent the true burden of disease with which governments must contend.

The factors contributing to these gender disparities are multifaceted. One possible contributing factor is the difference in average life expectancy between women and men. As women tend to have a longer lifespan, they are consequently at greater risk of developing DM and DR. In LMICs, women may have poorer access to healthcare services compared to men [18, 19]. Other factors that may contribute to disparities in eye health include, lack of access to information and resources, and lower literacy among females compared to males [20–22]. Pregnancy is another factor that can accelerate the progression of DR in women [23]. Finally, DR has been linked to intake of the retinal carotenoids lutein and zeaxanthin, and women are thought to have lower retinal levels of lutein and zeaxanthin [24, 25]. The difference in retinal levels of lutein and zeaxanthin between men and women may be due to several factors including hormones, dietary patterns, and variances in metabolic processes [25]. Factors such as smoking might vary between women and men, contributing to differences in retinal levels. This requires further investigation to ascertain the precise causes behind the observed differences in retinal levels between men and women. Action is needed to improve female care and reduce the burden of DR-related blindness and MSVI.

Teo et al. estimated that there would be 103.12 million people with DR, 28.54 million people with vision-threatening DR, and 18.83 million people with clinically significant macular oedema in 2020 [26]. They found that the North America and Caribbean (NAC) and Middle East and North Africa (MENA) showed significantly higher prevalence of DR compared to other regions [26]. Similarly, our results show that the Latin America and Caribbean and North Africa, and Middle East super-regions demonstrated the highest prevalence of DR-related blindness and MSVI. This may be attributed to several factors such as limited access to quality healthcare services, increased DM cases, and inadequate management of DM. Although DR is estimated to affect over 100 million people globally, our data from 2020 suggests that less than 1.1 million are currently blind and less than 3.3 million are visually impaired. Compared to the 2010 data, 834,000 people were blind whereas 3.7 million were visually impaired [8]. The decline in the number of people with MSVI from 2010, despite an increase in DR-related blindness may be due to advancements in medical technology and treatments for DR. They play a role in preventing the progression of the disease to more severe stages, hence reducing the number of individuals with MSVI. Additionally, increased awareness about DM and its ocular complications might lead to earlier detection and intervention, which could prevent or mitigate MSVI cases despite the rise in DR-related blindness.

Blindness and MSVI can have a profound impact on quality of life, impairing both mental and physical health, and social independence [27]. As reported in the GBD Study 2019, blindness and low vision was ranked eighth (contributing 3.8% [95% UI 3.0, 4.9]) of all years lived with disability (YLDs) in people aged 50–69 years [13]. Among people aged 70 years and older, blindness and low vision was ranked fourth (contributing 6.4% [5.4, 7.4] of all YLDs) [13]. Furthermore, blindness and MSVI are associated with reduced economic, educational, and employment opportunities [28–30]. Economic productivity at the individual, family, community, and national level is important to sustainable development. An inability to work can diminish the productive capacity of the economy by reducing the workforce. Illness and disability can contribute to productivity losses through absenteeism from work, reduced productivity while at work or unemployment, including job loss and early retirement [28–31]. The Lancet Global Health Commission on Global Eye Health assessed the overall relative reduction in employment by working-aged people with blindness
<table><caption>**Table 1.** Number of people (mean [95% UI]) with DR-related blindness (presenting visual acuity <3/60) or DR-related MSVI (presenting visual acuity <6/18, ≥3/60), the age-standardized prevalence (%) in people of all ages and aged ≥50 years (mean [95% UI]), and the percentage of all blindness or MSVI attributed to DR (95% UI) in 2020 by 7 GBD super-regions.</caption><thead><tr><th rowspan="2">World Region</th><th colspan="2">DR-related blindness in 2020</th><th colspan="4">DR-related MSVI in 2020</th></tr><tr><th>2020, Total population ('000 s)</th><th>Number of people ('000 s) with DR-related blindness in 2020 (all ages)</th><th>Age-standardized prevalence of DR-related blindness in 2020 (aged ≥ 50 years)</th><th>Percentage of all DR-related blindness per region in 2020 (≥50 years)</th><th>Number of people ('000 s) with DR-related MSVI in 2020 (all ages)</th><th>Age-standardized prevalence of DR-related MSVI in people ≥50 years aged in 2020</th><th>Percentage of DR-related MSVI per region in 2020 (≥50 years)</th></tr></thead><tbody><tr><td>Global</td><td>7,890,000</td><td>1,074 (763, 1514)</td><td>0.05 (0.03, 0.07)</td><td>2.50 (1.77, 3.52)</td><td>3278 (2409, 4344)</td><td>0.16 (0.12, 0.21)</td><td>1.11 (0.82, 1.47)</td></tr><tr><td>Central Europe, Eastern Europe, and Central Asia</td><td>417,291</td><td>13 (9, 19)</td><td>0.01 (0.01, 0.01)</td><td>0.97 (0.67, 1.39)</td><td>144 (102, 193)</td><td>0.09 (0.07, 0.13)</td><td>0.80 (0.57, 1.08)</td></tr><tr><td>High-income</td><td>1,087,856</td><td>161 (116, 227)</td><td>0.03 (0.02, 0.04)</td><td>5.37 (3.86, 7.55)</td><td>420 (308, 558)</td><td>0.08 (0.06, 0.11)</td><td>1.35 (0.99, 1.80)</td></tr><tr><td>Latin America and Caribbean</td><td>601,551</td><td>254 (185, 347)</td><td>0.15 (0.10, 0.21)</td><td>6.95 (5.08, 9.51)</td><td>451 (333, 598)</td><td>0.30 (0.22, 0.40)</td><td>1.84 (1.36, 2.45)</td></tr><tr><td>North Africa and Middle East</td><td>631,727</td><td>73 (50, 105)</td><td>0.06 (0.04, 0.09)</td><td>2.37 (1.63, 3.42)</td><td>462 (339, 609)</td><td>0.41 (0.30, 0.55)</td><td>2.12 (1.55, 2.79)</td></tr><tr><td>South Asia</td><td>1,841,435</td><td>196 (135, 285)</td><td>0.05 (0.03, 0.07)</td><td>1.65 (1.14, 2.39)</td><td>444 (323, 598)</td><td>0.13 (0.09, 0.17)</td><td>0.46 (0.34, 0.62)</td></tr><tr><td>Southeast Asia, East Asia, and Oceania</td><td>2,192,710</td><td>325 (222, 478)</td><td>0.04 (0.03, 0.06)</td><td>2.16 (1.48, 3.17)</td><td>1190 (862, 1593)</td><td>0.18 (0.13, 0.24)</td><td>1.43 (1.04, 1.92)</td></tr><tr><td>Sub-Saharan Africa</td><td>1,114,806</td><td>49 (35, 71)</td><td>0.03 (0.02, 0.05)</td><td>0.98 (0.69, 1.40)</td><td>164 (120, 217)</td><td>0.14 (0.10, 0.19)</td><td>0.81 (0.59, 1.06)</td></tr></tbody></table>

and MSVI [31]. They found that the global average relative reduction in employment of people with vision impairment was estimated to be 30.2% [31]. Since blindness and MSVI can have a large economic impact globally, more data on the employment status of people living with blindness and MSVI in all world regions, especially, LMICs needs to be available. Future research should explore more specifically how DR-related blindness and MSVI affect productivity losses and if there are relevant differences by sex.

We reviewed the literature to determine the economic burden of DR globally. According to UK estimates, DR has an annual cost of £379 million ($476 million) for cases linked to type 2 DM, and almost £14 million ($17.6 million) for cases related to type 1 DM [32]. Economic modeling in the UK suggests that reducing the prevalence of type 2 DM-related DR by just 1% each year could save the UK economy £150 million ($188.6 million) by 2050 [32]. The estimated economic burden of DR in the United States is $0.5 billion [33], $3.91 billion in Germany [34], and $3.5 to 6.4 billion in the Latin America and the Caribbean region [35]. Further exploration of the economic burden in all world regions is necessary for agenda setting and policy planning in the future.

## Strengths

The VLEG populates and curates the Global Vision Database, a continuously updated, comprehensive, online database storing worldwide ophthalmic epidemiological information, including DR. By considering data from Jan 1st 1980 to Oct 1st 2018, the study covers a significant period, allowing for the assessment of trends and changes over time. The inclusion of gray literature enriches the database with unpublished data yet valuable data.

Our report provides an update on the worldwide and regional estimates for DR-related blindness and MSVI, including the changing patterns over time. It demonstrates that considerable regional differences and sex inequalities exist, highlighting areas that require particular attention such as low resource settings. These findings could aid further region-specific DR healthcare policies to prevent vision impairment, especially among females in the future.

## Limitations

This meta-analysis has some limitations, such as potential publication bias and heterogeneity across studies. Due to the paucity of data across low burden regions, we may be over/under-estimating DR overall prevalence. While visual acuity is an important measure of visual function, it is not the only measure, and it is important to consider other methods of measuring visual impairment such as contrast sensitivity when assessing the prevalence of vision impairment. Nonetheless, our findings highlight the ongoing burden of DR-related vision impairment and underscore the need for effective prevention and management strategies.

Early detection and timely treatment are essential for preventing avoidable DR-related blindness and MSVI [36, 37]. Between 2000 and 2020, high-income countries have made good progress in terms of reducing their DR-related blindness/MSVI which may be linked to improved risk factor control and advances in their screening and treatment services [7, 38, 39]. Despite this success, screening and treatment services still remain a challenge for super-regions such as Latin America (high prevalence of all DR-related blindness and MSVI ≥50 years old) [40]. While Sub-Saharan Africa might be anticipated to have a higher burden of DR compared to regions such as Latin America and Caribbean, Middle East, and North Africa, differences in population demographics, genetics, lifestyle, and DM management approaches contribute to varied prevalence rates. Under-reporting and insufficient data availability further complicate assessing the true extent of the issue. While healthcare resources are limited in Sub-Saharan Africa, certain areas within the region may have stronger healthcare infrastructure or targeted interventions that improve DR management compared to other LMICs. The global
<table><caption>**Table 2.** Number of males and females with DR-related blindness (presenting visual acuity <3/60), and the age-standardized prevalence (% (95% UI)) of DR-related blindness (all ages and people aged ≥50 years) in 2020 by 7 GBD super-regions.</caption><thead><tr><th rowspan="2">World Region</th><th rowspan="2">Total population 2020 total population (000 s)</th><th colspan="3">Total number of DR-related blindness and age-standardized DR-related blindness in 2020 (all ages)</th><th colspan="3">Total number of DR-related blindness and age-standardized DR-related blindness in people aged 50+ years in 2020</th></tr><tr><th>Number of males with DR-related blindness in 2020</th><th>Number of females with DR-related blindness in 2020</th><th>Age-standardized prevalence of DR-related blindness in males in 2020</th><th>Number of males (50+ years) with DR-related blindness in 2020</th><th>Number of females (50+ years) with DR-related blindness in 2020</th><th>Age-standardized prevalence of DR-related blindness in males in 2020</th></tr></thead><tbody><tr><td>Global</td><td>7,890,000</td><td>462,927.18 (325,654.61–652,044.38)</td><td>611,103.46 (435,144.17–859,526.29)</td><td>0.01 (0.01, 0.02)</td><td>0.01 (0.01, 0.02)</td><td>367,532.63 (248,081.18–527,880.98)</td><td>493,647.89 (340,091.39–705,878.95)</td><td>0.04 (0.02, 0.06)</td><td>0.05 (0.03, 0.07)</td></tr><tr><td>Central Europe, Eastern Europe, and Central Asia</td><td>417,291</td><td>1755.87 (1093.16–2682.48)</td><td>11,965.13 (8,228.75–17,190.34)</td><td>0.00 (0.00, 0.00)</td><td>0.00 (0.00, 0.00)</td><td>1,481.80 (911.96–2301.54)</td><td>10,388.59 (7,004.18–15,046.41)</td><td>0.00 (0.00, 0.00)</td><td>0.01 (0.01, 0.02)</td></tr><tr><td>High-income</td><td>1,087,856</td><td>44,382.55 (30,587.44–64,097.86)</td><td>117,013.99 (84,406.34–162,072.26)</td><td>0.01 (0.00, 0.01)</td><td>0.01 (0.01, 0.02)</td><td>38,713.55 (25,822.71–57,277.14)</td><td>100,431.86 (71,172.17–138,889.24)</td><td>0.02 (0.01, 0.03)</td><td>0.04 (0.03, 0.06)</td></tr><tr><td>Latin America and Caribbean</td><td>601,551</td><td>126,678.01 (91,595.33–174,863.61)</td><td>127,505.49 (94,172.48–173,729.00)</td><td>0.04 (0.03, 0.06)</td><td>0.04 (0.03, 0.05)</td><td>99,032.99 (67,913.52–139,574.07)</td><td>103,802.70 (73,225.22–143,172.95)</td><td>0.16 (0.11, 0.22)</td><td>0.14 (0.10, 0.20)</td></tr><tr><td>North Africa and Middle East</td><td>631,727</td><td>40,410.14 (27,627.57–58,733.35)</td><td>32,864.35 (22,466.72–48,315.39)</td><td>0.02 (0.01, 0.02)</td><td>0.01 (0.01, 0.02)</td><td>33,270.71 (21,679.83–49,856.62)</td><td>27,733.97 (18,402.82–42,027.66)</td><td>0.07 (0.05, 0.10)</td><td>0.06 (0.04, 0.09)</td></tr><tr><td>South Asia</td><td>1,841,435</td><td>81988.27 (56304.46–117390.29)</td><td>114658.79 (79601.64–167678.53)</td><td>0.01 (0.01, 0.02)</td><td>0.02 (0.01, 0.02)</td><td>64620.90 (42826.69–94579.40)</td><td>87110.02 (57949.08–129720.46)</td><td>0.04 (0.03, 0.06)</td><td>0.05 (0.04, 0.08)</td></tr><tr><td>Southeast Asia, East Asia, and Oceania</td><td>2,192,710</td><td>148,475.37 (101,487.27–215,934.63)</td><td>176,643.96 (120,673.90–260,725.76)</td><td>0.01 (0.01, 0.02)</td><td>0.01 (0.01, 0.02)</td><td>116,365.81 (76,418.03–172,826.78)</td><td>144,301.43 (94,401.38–214,160.92)</td><td>0.04 (0.02, 0.06)</td><td>0.04 (0.03, 0.06)</td></tr><tr><td>Sub-Saharan Africa</td><td>1,114,806</td><td>19236.98 (13185.23–27388.12)</td><td>30451.75 (21586.92–43727.97)</td><td>0.01 (0.01, 0.01)</td><td>0.01 (0.01, 0.01)</td><td>14046.86 (9235.32–21084.33)</td><td>19879.33 (136457.8–28518.23)</td><td>0.03 (0.02, 0.05)</td><td>0.04 (0.03, 0.05)</td></tr></tbody></table>
<table><caption>**Table 3.** Number of males and females with DR-related MSVI, and the age-standardized prevalence (% [95% uncertainty intervals (UIs)] of DR-related MSVI (all ages and people aged ≥ 50 years) in 2020 by 7 GBD super-regions.</caption><thead><tr><th rowspan="2">World Region</th><th rowspan="2">2020 total population (100 s)</th><th colspan="2">Total number of DR-related MSVI and age-standardized DR-related MSVI in 2020</th><th colspan="2">Total number of DR-related MSVI and age-standardized DR-related MSVI in 50+ years in 2020</th><th colspan="2">Age-standardized prevalence of DR-related MSVI in males in 2020</th><th rowspan="2">Age-standardized prevalence of DR-related MSVI in females in 2020</th></tr><tr><th>Number of males with DR-related MSVI in 2020</th><th>Number of females with DR-related MSVI in 2020</th><th>Age-standardized prevalence of DR-related MSVI in males in 2020</th><th>Age-standardized prevalence of DR-related MSVI in 2020</th><th>Number of males (50+ years) with DR-related MSVI in 2020</th><th>Number of females (50+ years) with DR-related MSVI in 2020</th></tr></thead><tbody><tr><td>Global</td><td>7,890,000</td><td>1,434,563.64<br>(1,058,082.45–1,906,706.91)</td><td>1,843,470.26<br>(1,354,361.39–2,434,417.31)</td><td>0.04 (0.03, 0.05)</td><td>0.04 (0.03, 0.05)</td><td>1,283,152.12<br>(929,301.13–1,730,971.73)</td><td>1,662,787.39<br>(1,207,905.41–2,222,537.30)</td><td>0.15 (0.11, 0.20)</td><td>0.17 (0.12, 0.22)</td></tr><tr><td>Central Europe, Eastern Europe, and Central Asia</td><td>417,291</td><td>50,221.20<br>(35,532.76–67,893.80)</td><td>94,204.50<br>(66,934.75–124,937.93)</td><td>0.02 (0.01, 0.03)</td><td>0.02 (0.02, 0.03)</td><td>46,096.08<br>(32,051.61–63,189.24)</td><td>88,358.52<br>(62,275.75–118,849.35)</td><td>0.08 (0.06, 0.11)</td><td>0.10 (0.07, 0.14)</td></tr><tr><td>High-Income</td><td>1,087,856</td><td>168,636.22<br>(124,963.48–224,391.14)</td><td>251,401.81<br>(183,394.45–336,375.21)</td><td>0.02 (0.01, 0.02)</td><td>0.02 (0.02, 0.03)</td><td>151,688.80<br>(108,728.71–204,628.93)</td><td>233,889.33<br>(167,461.31–317,886.32)</td><td>0.07 (0.05, 0.10)</td><td>0.09 (0.06, 0.12)</td></tr><tr><td>Latin America and Caribbean</td><td>601,551</td><td>210,400.26<br>(155,349.78–282,311.45)</td><td>240,993.75<br>(177,872.69–318,631.42)</td><td>0.07 (0.06, 0.10)</td><td>0.07 (0.05, 0.10)</td><td>184,619.39<br>(133,297.98–249,704.02)</td><td>211,681.86<br>(153,838.77–284,165.76)</td><td>0.30 (0.22, 0.41)</td><td>0.29 (0.21, 0.39)</td></tr><tr><td>North Africa and Middle East</td><td>631,727</td><td>209,853.63<br>(154,123.75–277,168.06)</td><td>252,518.04<br>(186,029.20–333,427.73)</td><td>0.09 (0.07, 0.12)</td><td>0.11 (0.08, 0.15)</td><td>180,252.63<br>(130,165.51–244,813.42)</td><td>219,082.90<br>(158,244.71–295,314.20)</td><td>0.37 (0.27, 0.51)</td><td>0.45 (0.33, 0.61)</td></tr><tr><td>South Asia</td><td>1,841,435</td><td>195,237.80<br>(141,348.63–261,562.12)</td><td>249,304.72<br>(181,409.73–336,125.23)</td><td>0.03 (0.02, 0.04)</td><td>0.03 (0.02, 0.05)</td><td>170,861.07<br>(121,996.86–231,790.95)</td><td>217,902.35<br>(155,497.63–296,733.22)</td><td>0.11 (0.08, 0.15)</td><td>0.14 (0.10, 0.19)</td></tr><tr><td>Southeast Asia, East Asia, and Oceania</td><td>2,192,710</td><td>529,736.41<br>(382,298.34–712,821.22)</td><td>660,634.29<br>(480,541.67–876,817.85)</td><td>0.04 (0.03, 0.05)</td><td>0.04 (0.03, 0.06)</td><td>490,582.61<br>(352,372.31–665,085.13)</td><td>613,025.86<br>(442,398.51–825,577.13)</td><td>0.17 (0.12, 0.23)</td><td>0.19 (0.14, 0.25)</td></tr><tr><td>Sub-Saharan Africa</td><td>1,114,806</td><td>70,478.12<br>(51,543.64–93,966.89)</td><td>94,413.15<br>(69,139.60–124,855.35)</td><td>0.03 (0.02, 0.04)</td><td>0.04 (0.03, 0.05)</td><td>59,051.54<br>(42,153.34–80,066.25)</td><td>78,846.57<br>(56,570.77–107,274.46)</td><td>0.13 (0.10, 0.18)</td><td>0.15 (0.11, 0.20)</td></tr></tbody></table>
<figure><img src="image_3.png" /><figcaption>**Fig. 1** Prevalence of blindness and moderate to severe visual impairment (MSVI) due to diabetic retinopathy (DR) in 2020 across seven global burden of disease (GBD) super-regions. Crude prevalence of blindness and MSVI due to DR in 2020 by age, across seven world GBD super-regions. **a** Crude prevalence of blindness due to DR in 2020 by seven world GBD super-regions by age. The graph demonstrates an increase in prevalence with age, with notable variations between super-regions. The super-regions are represented by different coloured lines. **b** Crude prevalence of MSVI in 2020 by seven world GBD super-regions by age. Similar to (a), the prevalence increases with age, highlighting disparities among different super-regions. Each super-region is depicted by a distinct coloured line.</figcaption></figure>

burden of DR is expected to remain high through 2045, disproportionately affecting countries in the Middle East and North Africa, and the Western Pacific [26]. Delivering innovative DR prevention and treatment strategies to improve global eye health is necessary. Screening for DR would also be much improved by the existence of population DM registers. Finally, our findings suggest the need for region-specific healthcare policies aimed at preventing vision loss, particularly among females.

Supplemental material is available at Eye's website.

## SUMMARY

What was known before

* Globally, in 2020, 1.07 million people were blind, and nearly 3.28 million were visually impaired by diabetic retinopathy.

What this study adds

* The contribution of diabetic retinopathy and moderate and severe vision impairment (MSVI) by region and the change in this contribution between 2000 and 2020. The change in global age-standardized prevalence of DR-related blindness and MSVI between 2000 and 2020 and the differences by sex and region.

## DATA AVAILABILITY

The data that support the findings of this study are not openly available due to reasons of sensitivity and are available from the coordinator of the Vision Loss Expert Group (Professor Rupert Bourne; rb@rupertbourne.co.uk) upon reasonable request. Data are located in controlled access data storage at Anglia Ruskin University.

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## ACKNOWLEDGEMENTS

The funder of the study had no role in the study design, data collection, data analysis, data interpretation, or writing of the report. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication.

## AUTHOR CONTRIBUTIONS

Please see Appendix for more detailed information about individual author contributions to the research, divided into the following categories: managing the overall research enterprise; writing the first draft of the manuscript; primary responsibility for applying analytical methods to produce estimates; primary responsibility for seeking, cataloguing, extracting, or cleaning data; designing or coding figures and tables; providing data or critical feedback on data sources; developing methods or computational machinery; providing critical feedback on methods or results; drafting the manuscript or revising it critically for important intellectual content; and managing the estimation or publications process.

## FUNDING

This study was funded by Brien Holden Vision Institute, Fondation Thea, Fred Hollows Foundation, Bill & Melinda Gates Foundation, Lions Clubs International Foundation (LCIF), Sightsavers International, and University of Heidelberg.

## COMPETING INTERESTS

**GBD 2019 Blindness and Vision Impairment Collaborators:** T W Bärnighausen reports grants or contracts from the European Union (Horizon 2020 and EIT Health), German Research Foundation (DFG), US National Institutes of Health, German Ministry of Education and Research, Alexander von Humboldt Foundation, Else-Kröner-Fresenius-Foundation, Wellcome Trust, Bill & Melinda Gates Foundation, KfW, UNAIDS, and WHO; consulting fees from kfW on the OSCAR initiative in Vietnam; participation on a Data Safety Monitoring Board or Advisory Board with NIH-funded study "Healthy Options" (Pls: Smith Fawzi, Kaaya) as Chair of the Data Safety and Monitoring Board, German National Committee on the "Future of Public Health Research and Education" as Chair of the scientific advisory board to the EDCTP Evaluation, Member of the UNAIDS Evaluation Expert Advisory Committee, National Institutes of Health Study Section Member on Population and Public Health Approaches to HIV/AIDS (PPAH), US National Academies of Sciences, Engineering, and Medicine's Committee for the "Evaluation of Human Resources for Health in the Republic of Rwanda under the President's Emergency Plan for AIDS Relief (PEPFAR)", University of Pennsylvania (UPenn) Population Aging Research Center (PARC) as an External Advisory Board Member; leadership or fiduciary roles in board, society, committee or advocacy groups, paid or unpaid with the Global Health Hub Germany (which was initiated by the German Ministry of Health) as co-chair; all outside the submitted work. R Bourne reports support for the present manuscript to their institution, supporting the Vision Loss Expert Group, from the World Health Organization, the Brien Holden Vision Institute, Foundation Thea, Fred Hollows Foundation, Lions Clubs International Foundation; Bourne reports grants or contracts outside the submitted work to their institution supporting the Vision Loss Expert Group from Sightsavers International and University of Heidelberg. X Dai reports support for the present manuscript from the Institute for Health Metrics and Evaluation (University of Washington) for their salary. D S Friedman reports grants or contracts to their institution for research from Genentech; consulting fees from Abbvie, Kaliyope, Life Biosciences, Bausch and Lomb; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Thea Pharmaceuticals; support for attending meetings and travels from Thea Pharmaceuticals; leadership or fiduciary roles in board, society, committee or advocacy groups, paid or unpaid with Orbis International as a Member of the Board of Governors; all outside the submitted work. J M Furtado reports consulting fees outside the submitted work from SightFirst Latin America and Pan American Health Organization. V B Gupta reports grants or contracts from National Health and Medical Research Council (NHMRC) provided to Deakin University; outside the submitted work. V K Gupta reports grants or contracts from National Health and Medical Research Council (NHMRC) provided to Macquarie University; outside the submitted work. S M S Islam reports support for the present manuscript from the National Health and Medical Research Council (NHMRC, Australia) via an investigator grant and from the Heart Foundation of Australia via a Vanguard Grant. J E Kim reports consulting fees from Allergan, Apellis, Astellas, Bausch&Lomb, Clearside Biomedical, DORC, Genentech/Roche, Notal Vision, Outlook Therapeutics, and Regeneron; leadership or fiduciary roles in board, society,
committee or advocacy groups, unpaid, with American Society of Retina Specialists, Macula Society, American Academy of Ophthalmology, and NAEVR/AEVR; receipt of equipment for research from Optos; all outside the submitted work. K Krishan reports non-financial support from the UGC Centre of Advanced Study, CAS II, awarded to the Department of Anthropology, Panjab University (Chandigarh, India); outside the submitted work. J L Leasher reports leadership or fiduciary roles in board, society, committee or advocacy groups, unpaid as a member of the National Eye Institute National Eye Health Education Program planning committee; outside the submitted work. J D Steinmetz reports support for the present manuscript from the Bill and Melinda Gates Foundation IHME funding for GBD analyses. Y Tan reports support for the present manuscript from the Department of Ophthalmology, The Third Xiangya Hospital, Central South University and the Postdoctoral Station of Clinical Medicine, The Third Xiangya Hospital, Central South University. F Topouzis reports grants or contracts from Thea Pharma Inc., Omikron, Pfizer, Alcon, AbbVie, Bayer, paid to their institution; consulting fees paid to them from Thea Pharma Inc., Omikron, Bausch & Lomb; participation on a Data Safety Monitoring Board or Advisory Board with Omikron, paid to them, and AbbVie and Roche, paid to their institution; leadership or fiduciary roles in board, society, committee or advocacy groups, unpaid, with European Glaucoma Society as President, Greek Glaucoma Society as President, and World Glaucoma Association as member of the Board of Governors; all outside the submitted work. **Vision Loss Expert Group of the Global Burden of Disease Study:** A Bron reports payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Théa. M A Del Monte reports support for attending meetings and/or travel from the University of Michigan, and leadership or fiduciary roles in board, society, committee or advocacy groups, paid or unpaid as past president of Costenbader Society. D Friedman reports receipt of equipment, materials, drugs, medical writing, gifts or other services from LumenisCorp (instrumental loan). J M Furtado reports consulting fees from Pan American Health Organization and from Lions Club International Foundation. G Gazzard reports consulting fees from Alcon Laboratories, Inc; Allergan, Inc; BELKIN Vision LTD; Carl Zeiss Meditec; Elios; Genentech/Roche; Reichert; Théa and ViaLase; payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Alcon Laboratories, Inc; BELKIN Vision Ltd; Carl Zeiss Meditec; Elios and Ellex; participation on a Data Safety Monitoring Board or Advisory Board with Alcon Laboratories, Inc; Allergan, Inc; BELKIN Vision Ltd; Carl Zeiss Meditec; Elios and Visufarma; and leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid with Glaucoma UK Medical Advisory Board and UK&Eire Glaucoma Society as president. M E Hartnett reports support for the present manuscript (e.g., funding, provision of study materials, medical writing, article processing charges, etc.) from Michael F. Marmor, M.D. Professor of Retinal Science and Disease as endowment to support salary; grants or contracts from any entity (from National Eye Institute R01 EY017011 and National Eye Institute R01 EY015130) as partial salary support; patents planned, issued or pending (WO2015123561A2 and WO2021062169A1); and leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid with Jack McGovern Coats' Disease Foundation and as director of Women's Eye Health and Macular Society Grant Review Chair. J H Kempen reports support for the present manuscript (e.g., funding, provision of study materials, medical writing, article processing charges, etc.) from Mass Eye and Ear Global Surgery Program (as support of salary); grants or contracts from any entity from Sight for Souls (as support of salary); and stock or stock options with Betaliq and Tarsier (both as small equity owner). J E Kim reports consulting fees from Genentech/Roche, DORC, Notal Vision and Outlook Therapeutics (all as payment to J E Kim); participation on a Data Safety Monitoring Board or Advisory Board with Allergan, Amgen, Apellis, Bausch&Lomb, Clearside, Coherus, Novartis and Regeneron (all as participation on advisory board); leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid, with AAO, APRIS, ASRS, Macular Society and NAEVR/AEVR (all unpaid); and receipt of

equipment, materials, drugs, medical writing, gifts or other services from Clearside and Genentech/Roche (both for medical writing). V C Lansing reports consulting fees from HelpMeSee (as an employee); and support for attending meetings and/or travel from HelpMeSee (pay airfare and hotel). J Leasher reports leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid with National Eye Institute (as a member) and National Eye Health Education Program planning committee (unpaid). M Nowak reports participation on a Data Safety Monitoring Board or Advisory Board with Vision Express Co. Poland as the chairman of medical advisory board of Vision Express Co. Poland. T Peto reports grants or contracts from any entity from Novartis (paid to institution); payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Bayer, Novartis and Roche (paid to T Peto); and leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid with European Association for Diabetic Eye Complications as current president (unpaid). P Ramulu reports grants or contracts from National Institute of Health and Perfuse Therapeutics; and consulting fees from Alcon and W. L. Gore. F Topouzis reports grants or contracts from Théa, Omikron, Pfizer, Alcon, Abbvie and Bayer (all paid to Institution); consulting fees from Omikron, Théa and Bausch & Lomb (all paid to Topouzis); payment or honoraria for lectures, presentations, speakers bureaus, manuscript writing or educational events from Omikron (paid to Topouzis), Abbvie and Roche (both paid to Institute); and leadership or fiduciary role in other board, society, committee or advocacy group, paid or unpaid with European Glaucoma Society (as president), Greek Glaucoma Society (as president) and Board of Governors, World Glaucoma Association (all unpaid).

## ADDITIONAL INFORMATION

**Supplementary information** The online version contains supplementary material available at https://doi.org/10.1038/s41433-024-03101-5.

**Correspondence** and requests for materials should be addressed to Rupert R. A. Bourne.

**Reprints and permission information** is available at http://www.nature.com/reprints

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<figure><img src="image_4.png" /></figure>

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© The Author(s) 2024

## VISION LOSS EXPERT GROUP OF THE GLOBAL BURDEN OF DISEASE STUDY

Katie Curran<fnref n="1" />, Tunde Peto<fnref n="1" />, Jost B. Jonas², David Friedman³, Judy E. Kim⁴, Janet Leasher⁵, Ian Tapply⁶, Arthur G. Fernandes⁷,⁸, Maria Vittoria Cicinelli⁹,¹⁰, Alessandro Arrigo¹¹, Nicolas Leveziel¹²,¹³, Serge Resnikoff¹⁴,¹⁵, Hugh R. Taylor¹⁶, Tabassom Sedighi¹⁷, Seth Flaxman¹⁸, Mukkharram M. Bikbov¹⁹, Tasanee Braithwaite²⁰,²¹, Alain Bron²², Ching-Yu Cheng²³,²⁴, Monte A. Del Monte²⁵,²⁶, Joshua R. Ehrlich²⁷,²⁸, João M. Furtado²⁹, Gus Gazzard³⁰, M. Elizabeth Hartnett³¹, Rim Kahloun³², John H. Kempen³³,³⁴,³⁵,³⁶, Moncef Khairallah³⁷, Rohit C. Khanna³⁸,³⁹,⁴⁰,⁴¹, Van Charles Lansing⁴²,⁴³,⁴⁴, Kovin S. Naidoo⁴⁰,⁴⁵, Vinay Nangia⁴⁶, Michal Nowak⁴⁷, Konrad Pesudovs⁴⁸, Pradeep Ramulu⁴⁹, Fotis Topouzis⁵⁰, Mitiadis Tsilimbaris⁵¹, Ya Xing Wang⁵², Ningli Wang⁵³ and Rupert R. A. Bourne¹⁷,¹⁸,⁴⁰

<footnote n="1">¹Centre for Public Health, Queens University Belfast, Belfast, Northern Ireland. ²Department of Ophthalmology, Medical Faculty Mannheim, Heidelberg University, Heidelberg, Germany. ³Mass Eye and Ear, Harvard Medical School, Boston, MA, USA. ⁴University of Texas Southwestern Medical Center, Dallas, TX, USA. ⁵Nova Southeastern University College for Optometry, Fort Lauderdale, FL, USA. ⁶Department of Ophthalmology, Cambridge University Hospitals, Cambridge, UK. ⁷Federal University of Sao Paolo, Sao Paolo/</footnote>
SP, Brazil.⁸University of Calgary, Calgary/AB, Canada.⁹School of Medicine, Vita-Salute San Raffaele University, Milan, Italy.¹⁰Department of Ophthalmology, IRCCS San Raffaele Scientific Institute, Milan, Italy.¹¹Scientific Institute San Raffaele Hospital, Vita-Salute University, Milan, Italy.¹²University of Poitiers, Poitiers, France.¹³CHU de Poitiers, Poitiers, France.¹⁴Brien Holden Vision Institute, Sydney, NSW, Australia.¹⁵School of Optometry and Vision Sciences, Faculty of Medicine, University of New South Wales, Sydney, NSW, Australia.¹⁶School of Population and Global Health, University of Melbourne, Carlton, VIC, Australia.¹⁷Vision and Eye Research Institute, Anglia Ruskin University, Cambridge, UK.¹⁸Department of Computer Science, University of Oxford, Oxford, UK.¹⁹Ufa Eye Research Institute, Ufa, Russia.²⁰School of Life Course and Population Sciences, King's College London, London, UK.²¹The Medical Eye Unit, Guy's and St Thomas' NHS Foundation Trust, London, UK.²²University Hospital, Dijon, France.²³National University of Singapore, Singapore, Singapore.²⁴Singapore Eye Research Institute, Singapore, Singapore.²⁵University of Michigan, Ann Arbor, MI, USA.²⁶Kellogg Eye Center, Ann Arbor, MI, USA.²⁷Institute for Social Research, University of Michigan, Ann Arbor, MI, USA.²⁸Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI, USA.²⁹Ribeirão Preto Medical School, University of São Paulo, São Paulo, Brazil.³⁰Institute of Ophthalmology UCL & NIHR Biomedical Research Centre, London, UK.³¹Stanford University, Stanford, CA, USA.³²Associated Ophthalmologists of Monastir, Monastir, Tunisia.³³Department of Ophthalmology, Harvard University, Boston, MA, USA.³⁴Eye Unit, MyungSung Medical College, Addis Ababa, Ethiopia.³⁵Department of Ophthalmology, Addis Ababa University, Addis Ababa, Ethiopia.³⁶Sight for Souls, Bellevue, WA, USA.³⁷Fattouma Bourguiba University Hospital, University of Monastir, Monastir, Tunisia.³⁸Allen Foster Community Eye Health Research Centre, Gullapalli Pratibha Rao International Centre for Advancement of Rural Eye care, L.V. Prasad Eye Institute, Hyderabad, India.³⁹Brien Holden Eye Research Centre, L.V. Prasad Eye Institute, Banjara Hills, Hyderabad, India.⁴⁰School of Optometry and Vision Science, University of New South Wales, Sydney, NSW, Australia.⁴¹University of Rochester, School of Medicine and Dentistry, Rochester, NY, USA.⁴²HelpMeSee, Instituto Mexicano de Oftalmologia, Santiago de Querétaro, Mexico.⁴³University of Miami, Miami, FL, USA.⁴⁴University of Utah, Salt Lake City, UT, USA.⁴⁵African Vision Research Institute, University of KwaZulu-Natal (UKZN), Durban, South Africa.⁴⁶Suraj Eye Institute, Nagpur, India.⁴⁷Institute of Optics and Optometry, University of Social Science, 121 Gdanska str., Lodz 90-519, Poland.⁴⁸Medicine & Health, University of New South Wales, Sydney, NSW, Australia.⁴⁹John Hopkins Wilmer Eye Institute, Baltimore, MD, USA.⁵⁰1st Department of Ophthamology, Medical School, Aristotle University of Thessaloniki, Ahepa Hospital, Thessaloniki, Greece.⁵¹University of Crete Medical School, Giofrirakia, Greece.⁵²Beijing Institute of Ophthamology, Beijing Tongren Hospital, Capital Medical University, Beijing Ophthamology and Visual Sciences Key Laboratory, Beijing, China.⁵³Beijing Institute of Ophthamology, Beijing Tongren Eye Center, Beijing Tongren Hospital, Capital Medical University, Beijing, China.¹⁸⁴These authors contributed equally: Rupert R. A. Bourne, Jaimie D. Steinmetz. email: rb@rupertbourne.co.uk.

THE GBD 2019 BLINDNESS AND VISION IMPAIRMENT COLLABORATORS

Katie Curran⁵⁴, Tunde Peto⁵⁴, Rupert Bourne⁵⁵, Janet L. Leasher⁵⁶, Jost B. Jonas⁵⁷,⁵⁸, Tabassom Sedighi¹⁷, David S. Friedman⁵⁹, Judy E. Kim⁶⁰, Arthur G. Fernandes⁶¹, Bright Opoku Ahinkorah⁶², Hamid Ahmadieh⁶³,⁶⁴, Ayman Ahmed⁶⁵,⁶⁶, Ahmad Samir Alfaar⁶⁷,⁶⁸, Louay Almidani⁶⁹,⁷⁰, Hubert Amu⁷¹, Sofia Androudi⁷², Jalal Arabloo⁷³, Aleksandr Y. Aravkin⁷⁴,⁷⁵,⁷⁶, Mulu Tiruneh Asemu⁷⁷, Ahmed Y. Azzam⁷⁸,⁷⁹, Nayereh Baghcheghi⁸⁰, Freddie Bailey⁸¹, Mehmet Firat Baran⁸², Mainak Bardhan⁸³, Till Winfried Bärnighausen⁸⁴,⁸⁵, Amadou Barrow⁸⁶,⁸⁷, Pankaj Bhardwaj⁸⁸,⁸⁹, Mukharram Bikbov⁹⁰, Tasanee Braithwaite⁹¹,⁹², Paul Svitil Briant⁷⁵, Katrin Burkart⁷⁵,⁷⁶, Luis Alberto Cámara⁹³,⁹⁴, Kaleb Coberly⁷⁵, Omid Dadras⁹⁵,⁹⁶, Xiaochen Dai⁷⁵,⁷⁶, Amin Dehghan⁹⁷, Berecha Hundessa Demessa⁹⁸, Mengistie Diress⁹⁹, Thanh Chi Do¹⁰⁰, Thao Huynh Phuong Do¹⁰¹, Klara Georgieva Dokova¹⁰², Bruce B. Duncan¹⁰³, Michael Ekholuenetale¹⁰⁴,¹⁰⁵, Muhammed Elhadi¹⁰⁶, Mohammad Hassan Emamian¹⁰⁷, Mehdi Emamverdi¹⁰⁸, Hossein Farrokhpour¹⁰⁹,¹¹⁰, Ali Fatehizadeh¹¹¹, Lorenzo Ferro Desideri¹¹², João M. Furtado¹¹³, Mesfin Gebrehiwot¹¹⁴, Fariba Ghassemi¹¹⁵, Mesay Dechasa Gudeta¹¹⁶, Sapna Gupta¹¹⁷, Veer Bala Gupta¹¹⁸, Vivek Kumar Gupta¹¹⁹, Billy Randall Hammond¹²⁰, Mehdi Harorani¹²¹, Hamidreza Hasani¹²², Golnaz Idaridi¹²³, Mehdi Hosseinzadeh¹²⁴,¹²⁵, John J. Huang¹²⁶, Sheik Mohammed Shariful Islam¹²⁷,¹²⁸, Nilofer Javadi¹²⁹,¹³⁰, Aida Jimenez-Corona¹³¹,¹³², Mohammad Jokar¹³³,¹³⁴, Charity Ehimwenma Joshua¹³⁵, Vidya Kadashetti¹³⁶, Himal Kandel¹³⁷,¹³⁸, Hengameh Kasraei¹³⁹,¹⁴⁰, Rimple Jeet Kaur¹⁴¹, Sudarshan Khanal¹⁴², Zahra Khorrami¹⁴³, Hamid Reza Koohestani¹⁴⁴, Kewal Krishan¹⁴⁵, Stephen S. Lim⁷⁵,⁷⁶, Mohammed Magdy Abd El Razek¹⁴⁶, Vahid Mansouri¹⁴⁷, Andrea Maugeri¹⁴⁸, Tomislav Mestrovic¹⁵,¹⁴⁹, Awoke Misganaw⁷⁶,¹⁵⁰, Ali H. Mokdad⁷⁵,⁷⁶, Hamed Momeni-Moghaddam¹⁵¹,¹⁵², Sara Momtazmanesh¹⁰⁹,¹⁵³, Christopher J. L. Murray⁷⁵,⁷⁶, Hadush Negash¹⁵⁴, Uchechukwu Levi Osuagwu¹⁵⁵,¹⁵⁶, Shahina Pardhan¹⁷, Jay Patel¹⁵⁷,¹⁵⁸, Shrikant Pawar¹⁵⁹, Ionela-Roxana Petcu¹⁶⁰, Hoang Tran Pham¹⁶¹, Mohsen Pourazizi¹⁶², Ibrahim Qattea¹⁶³, Mosiur Rahman¹⁶⁴, Umar Saeed¹⁶⁵,¹⁶⁶, Amirhossein Sahebkar¹⁶⁷,¹⁶⁸, Mohammad Amin Salehi¹⁶⁹, Maryam Shaydn¹⁷⁰,¹⁷¹, Aumin Shittu¹⁷², Jaimie D. Steinmetz¹⁵,¹⁸⁴, Yao Tan¹⁷³, Hugh R. Taylor¹⁶, Fotis Topouzis¹⁷⁴, Aristidis Tsatsakis¹⁷⁵, Muhammad Umair¹⁷⁶,¹⁷⁷, Theo Vos⁷⁵,⁷⁶, Hong Xiao¹⁷⁸,¹⁷⁹, Yuyi You¹³⁷,¹⁸⁰, Mikhail Sergeevich Zastrozhin¹⁸¹,¹⁸², Zhi-Jiang Zhang¹⁸³ and Peng Zheng⁷⁵,⁷⁶

⁵⁴Centre for Public Health, Queen's University Belfast, Belfast, UK.⁵⁵Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, UK.⁵⁶College of Optometry, Nova Southeastern University, Fort Lauderdale, FL, USA.⁵⁷Institute of Molecular and Clinical Ophthalmology Basel, Basel, Switzerland.⁵⁸Department of Ophthalmology, Heidelberg University, Mannheim, Germany.⁵⁹Mass Eye and Ear Department of Ophthalmology, Harvard Medical School, Boston, MA, USA.⁶⁰Department of Ophthalmology and Visual Sciences, Medical College of Wisconsin, Milwaukee, WI, USA.⁶¹Department of Ophthalmology and Visual Sciences, Federal University of São Paulo, São Paulo, Brazil.⁶²School of Public Health, University of Technology Sydney, Sydney, NSW, Australia.⁶³Ophthalmic Research Center, Shahid Beheshti University of Medical Sciences, Tehran, Iran.⁶⁴Department of Ophthalmology, Shahid Beheshti University of Medical Sciences, Tehran, Iran.⁶⁵Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan.⁶⁶Swiss Tropical and Public Health Institute, University of Basel, Basel, Switzerland.⁶⁷Department of Ophthalmology, University of Leipzig Medical Center, Leipzig, Germany.⁶⁸Department of Ophthalmology, Charité Medical University Berlin, Berlin, Germany.⁶⁹Wilmer Eye Institute, Johns Hopkins University School of Medicine, Baltimore, MD, USA.⁷⁰Doheny Image Reading and Research Lab (DIRRL) - Doheny Eye Institute, University of California Los Angeles, Los Angeles, CA, USA.⁷¹Department of Population and Behavioural Sciences, University of Health and Allied Sciences, Ho, Ghana.⁷²Department of Medicine, University of Thessaly, Volos, Greece.⁷³Health Management and Economics Research Center, Iran University of Medical Sciences, Tehran, Iran.⁷⁴Department of Applied Mathematics, University of Washington, Seattle, WA, USA.⁷⁵Institute for Health Metrics and Evaluation, University of Washington, Seattle, WA, USA.⁷⁶Department of Health Metrics Sciences, School of Medicine, University of Washington, Seattle, WA, USA.⁷⁷Department of Public Health, Debre Tabor University, Debre Tabor, Ethiopia.⁷⁸Department of Neurovascular Research, Nested Knowledge, Inc., Saint Paul, MN, USA.⁷⁹Faculty of Medicine, October 6 University, 6th of October City, Egypt.⁸⁰Department of Nursing, Saveh University of Medical Sciences, Saveh, Iran.⁸¹Big Data Institute - GRAM Project, University of Oxford, Oxford, UK.⁸²Vocational School of Technical Sciences, Batman University, Batman, Türkiye.⁸³Miami Cancer Institute, Baptist Health South Florida, Miami, FL, USA.⁸⁴Heidelberg Institute of Global Health (HIGH), Heidelberg University, Heidelberg, Germany.⁸⁵T.H. Chan School of Public Health, Harvard University, Boston, MA, USA.⁸⁶Department of Epidemiology, University of Florida, Gainesville, FL, USA.⁸⁷Department of Public & Environmental Health, University of The Gambia, Brikama, The Gambia.⁸⁸Department of Community Medicine and Family Medicine, All India Institute of Medical Sciences, Jodhpur, India.⁸⁹School of Public Health, All India Institute of Medical Sciences, Jodhpur, India.⁹⁰Epidemiology Department, Ufa Eye Research Institute, Ufa, Russia.⁹¹Ophthalmology Department, Moorfields Eye Hospital NHS Foundation Trust, London, UK.⁹²International Centre for Eye Health, London School of Hygiene & Tropical Medicine, London, UK.⁹³Internal Medicine Department, Hospital Italiano de Buenos Aires (Italian Hospital of Buenos Aires), Buenos Aires, Argentina.⁹⁴Board of Directors, Argentine Society of Medicine, Buenos Aires, Argentina.⁹⁵Department of Addiction Medicine, Haukland University Hospital, Bergen, Norway.⁹⁶Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway.⁹⁷School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.⁹⁸USAID-JSI, Jimma University, Addis Ababa, Ethiopia.⁹⁹Department of Human Physiology, University of Gondar, Gondar, Ethiopia.¹⁰⁰Department of Medicine, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Viet Nam.¹⁰¹Department of Medicine, Can Tho University of Medicine and
Pharmacy, Can Tho, Viet Nam. ¹⁰²Department of Social Medicine and Health Care Organisation, Medical University “Prof. Dr. Paraskev Stoyanov”, Varna, Bulgaria.

¹⁰³Postgraduate Program in Epidemiology, Federal University of Rio Grande do Sul, Porto Alegre, Brazil. ¹⁰⁴Department of Epidemiology and Medical Statistics, University of Ibadan, Ibadan, Nigeria. ¹⁰⁵Faculty of Public Health, University of Ibadan, Ibadan, Nigeria. ¹⁰⁶Faculty of Medicine, University of Tripoli, Tripoli, Libya. ¹⁰⁷Ophthalmic Epidemiology Research Center, Shahroud University of Medical Sciences, Shahroud, Iran. ¹⁰⁸Department of Ophthalmology, University of California Los Angeles, Los Angeles, CA, USA.

¹⁰⁹School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. ¹¹⁰Endocrinology and Metabolism Research Institute, Non-Communicable Diseases Research Center (NCDRC), Tehran, Iran. ¹¹¹Department of Environmental Health Engineering, Isfahan University of Medical Sciences, Isfahan, Iran. ¹¹²University Eye Clinic, University of Genoa, Genoa, Italy. ¹¹³Division of Ophthalmology, University of São Paulo, Ribeirão Preto, Brazil. ¹¹⁴Department of Environmental Health, Wollo University, Dessie, Ethiopia.

¹¹⁵Ophthalmology Department, Tehran University of Medical Sciences, Tehran, Iran. ¹¹⁶Department of Clinical Pharmacy, Haramaya University, Harar, Ethiopia. ¹¹⁷Toxicology Department, Shriram Institute for Industrial Research, Delhi, India. ¹¹⁸School of Medicine, Deakin University, Geelong, VIC, Australia. ¹¹⁹Faculty of Medicine Health and Human Sciences, Macquarie University, Sydney, NSW, Australia. ¹²⁰Brain and Behavioral Sciences Program, University of Georgia, Athens, GA, USA. ¹²¹Department of Nursing, Arak University of Medical Sciences, Arak, Iran. ¹²²Department of Ophthalmology, Iran University of Medical Sciences, Karaj, Iran. ¹²³Independent Consultant, Santa Clara, CA, USA.

¹²⁴Institute of Research and Development, Duy Tan University, Da Nang, Viet Nam. ¹²⁵Department of Computer Science, University of Human Development, Sulaymaniyah, Iraq.

¹²⁶Department of Ophthalmology and Visual Science, Yale University, New Haven, CT, USA. ¹²⁷Institute for Physical Activity and Nutrition, Deakin University, Burwood, VIC, Australia. ¹²⁸Sydney Medical School, University of Sydney, Sydney, NSW, Australia. ¹²⁹Student Research Committee, School of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran. ¹³⁰Department of Pediatrics, Isfahan University of Medical Sciences, Isfahan, Iran. ¹³¹Department of Ocular Epidemiology and Visual Health, Institute of Ophthalmology Foundation Conde de Valencia, Mexico City, Mexico. ¹³²Directorate General of Epidemiology, Mexico City, Mexico. ¹³³Zoonoses Research Center, Islamic Azad University, Karaj, Iran. ¹³⁴Department of Clinical Sciences, Jahrom University of Medical Sciences, Jahrom, Iran. ¹³⁵Department of Economics, National Open University, Benin City, Nigeria. ¹³⁶Department of Oral and Maxillofacial Pathology, Krishna Vishwa Vidyapeeth (Deemed to be University), Karad, India. ¹³⁷Save Sight Institute, University of Sydney, Sydney, NSW, Australia. ¹³⁸Sydney Eye Hospital, South Eastern Sydney Local Health District, Sydney, NSW, Australia. ¹³⁹Eye Research Center, Iran University of Medical Sciences, Tehran, Iran. ¹⁴⁰Health Policy Research Center, Shiraz University of Medical Sciences, Shiraz, Iran. ¹⁴¹Department of Pharmacology, All India Institute of Medical Sciences, Jodhpur, India. ¹⁴²Research Department, Better Vision Foundation Nepal, Kathmandu, Nepal. ¹⁴³Ophthalmology and Vision Science, Shahid Beheshti University of Medical Sciences, Tehran, Iran. ¹⁴⁴Social Determinants of Health Research Center, Saveh University of Medical Sciences, Saveh, Iran. ¹⁴⁵Department of Anthropology, Panjab University, Chandigarh, India. ¹⁴⁶Ophthalmology Department, Ministry of Health & Population, Aswan, Egypt. ¹⁴⁷Digestive Diseases Research Institute, Tehran University of Medical Sciences, Tehran, Iran. ¹⁴⁸Department GF Ingrassia, University of Catania, Catania, Italy. ¹⁴⁹University Centre Varazdin, University North, Varazdin, Croatia. ¹⁵⁰National Data Management Center for Health, Ethiopian Public Health Institute, Addis Ababa, Ethiopia. ¹⁵¹Optometry & Vision Sciences, Zahedan University of Medical Sciences, Zahedan, Iran.

¹⁵²Eye Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. ¹⁵³Non-communicable Diseases Research Center, Tehran University of Medical Sciences, Tehran, Iran. ¹⁵⁴Department of Medical Laboratory Sciences, Adigrat University, Adigrat, Ethiopia. ¹⁵⁵School of Medicine, Western Sydney University, Campbelltown, NSW, Australia.

¹⁵⁶Department of Optometry and Vision Science, University of KwaZulu-Natal, KwaZulu-Natal, South Africa. ¹⁵⁷Global Health Governance Programme, University of Edinburgh, Edinburgh, UK. ¹⁵⁸School of Dentistry, University of Leeds, Leeds, UK. ¹⁵⁹Department of Genetics, Yale University, New Haven, CT, USA. ¹⁶⁰Department of Statistics and Econometrics, Bucharest University of Economic Studies, Bucharest, Romania. ¹⁶¹Medical School, Pham Ngoc Thach University of Medicine, Ho Chi Minh City, Viet Nam.

¹⁶²Ophthalmology department, Isfahan University of Medical Sciences, Isfahan, Iran. ¹⁶³Department of Neonatology, Case Western Reserve University, Cleveland, OH, USA.

¹⁶⁴Department of Population Science and Human Resource Development, University of Rajshahi, Rajshahi, Bangladesh. ¹⁶⁵Multidisciplinary Laboratory Foundation University School of Health Sciences (FUSH), Foundation University, Islamabad, Pakistan. ¹⁶⁶International Center of Medical Sciences Research (ICMSR), Islamabad, Pakistan. ¹⁶⁷Applied Biomedical Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.

¹⁶⁸Biotechnology Research Center, Mashhad University of Medical Sciences, Mashhad, Iran. ¹⁶⁹Department of Medicine, Tehran University of Medical Sciences, Tehran, Iran. ¹⁷⁰Department of Ophthalmology, Harvard Medical School, Boston, MA, USA. ¹⁷¹Ophthalmic Research Center (ORC), Shahid Beheshti University of Medical Sciences, Tehran, Iran. ¹⁷²Department of Veterinary Public Health and Preventive Medicine, Usmanu Danfodiyo University, Sokoto, Sokoto, Nigeria. ¹⁷³Aier Eye Hospital, Jinan university, Guangzhou, China. ¹⁷⁴¹st Department of Ophthalmology, Aristotle University of Thessaloniki, Thessaloniki, Greece. ¹⁷⁵Department of Medicine, University of Crete, Heraklion, Greece. ¹⁷⁶Medical Genomics Research Department, King Abdullah International Medical Research Center, Riyadh, Saudi Arabia. ¹⁷⁷Department of Life Sciences, University of Management and Technology, Lahore, Pakistan. ¹⁷⁸School of Public Health, Zhejiang University, Zhejiang, China. ¹⁷⁹Department of Public Health Science, Fred Hutchinson Cancer Research Center, Seattle, WA, USA. ¹⁸⁰Macquarie Medical School, Macquarie University, Sydney, NSW, Australia. ¹⁸¹Department of Bioengineering and Therapeutic Sciences, University of California San Francisco, San Francisco, CA, USA. ¹⁸²Addictology Department, Russian Medical Academy of Continuous Professional Education, Moscow, Russia. ¹⁸³School of Medicine, Wuhan University, Wuhan, China.