Global, regional, and national burden of vision impairment from 1990 to 2021, with projections of prevalence to 2050

To the Editor: Vision loss is a major public health and socioeconomic issue, limiting access to education, employment, and quality of life. Although studies from 1980 to 2018 show a global decline in the age-standardized prevalence rate (ASPR) of blindness,1 they did not analyze the specific causes or severity-based trends of vision impairment. Research focusing on particular populations and regions also lacks a severity-based global perspective and future projections. Major causes of vision loss worldwide include refractive errors, cataracts, macular degeneration, glaucoma, and diabetic retinopathy. Vision impairment is classified into moderate (0.2 indicating high inequality. Analyses were performed using R (v4.3.2; The R Foundation for Statistical Computing; Vienna, Austria) with packages including ggplot2, data.table, tidyverse, MASS, and car, and Stata (v15.1; StataCorp LLC; College Station, Texas, USA) for CII calculation. All estimates included 95% confidence intervals. Future trends from 2022 to 2050 were projected using a Bayesian Age-Period-Cohort (BAPC) model, assuming log-linear Poisson distributions with ± 1% annual change bounds, implemented in the R package BAPC (v0.0.36). According to GBD 2021, the global prevalence of moderate vision loss, severe vision loss, and blindness in 2021 was 251.2 million, 29.3 million, and 34.2 million, respectively Table 1. Among 204 countries, Côte d’Ivoire showed the fastest increase in ASPR for all three levels of vision loss, with AAPCs of 2.64%, 2.22%, and 1.22%. The Northern Mariana Islands had the fastest rise in age-standardized YLD rates (ASDR) due to moderate vision loss and blindness (AAPCs: 2.55% and 1.95%), while Côte d’Ivoire led in severe vision loss (AAPC: 3.31%). Detailed results are in Supplementary Tables 1–3, https://links.lww.com/CM9/C809. Globally, Western Sub-Saharan Africa had the highest ASPR increase in moderate vision loss (16.8%), while South Asia showed the greatest reductions in moderate (−13.2%), severe (−19.9%), and blind (−49.9%) vision loss Supplementary Figure 1A, https://links.lww.com/CM9/C809. Regional changes in ASDR are shown in Supplementary Figure 1B, https://links.lww.com/CM9/C809. Table 1 - Trend changes in different severity levels of vision impairment for the prevalence and YLDs indicators. Measures Variables 1990 Number (95% UI) 1990 ASR (95% UI), per 100,000 population 2021 Number (95% UI) 2021 ASR (95% UI), per 100,000 population AAPC of ASR (95% CI), %/year P values Prevalence Moderate vision loss Global 128,407,948.67 (115,254,368.90 to 142,394,863.68) 2,941.11 (2,639.27 to 3,270.22) 251,225,048.67 (225,507,917.14 to 280,646,164.19) 2,989.95 (2,686.11 to 3,321.65) 0.07 (0.06 to 0.08) 0.001 Gender Male 58,315,491.88 (52,429,172.70 to 64,962,537.25) 2,815.70 (2,524.34 to 3,127.29) 112,421,328.26 (100,589,868.35 to 125,736,488.80) 2,814.69 (2,527.97 to 3,119.60) 0.01 (−0.01 to 0.08) 0.065 Female 70,092,456.79 (63,048,925.68 to 77,584,491.19) 3,061.56 (2,747.35 to 3,405.84) 138,803,720.41 (124,655,817.30 to 154,880,520.76) 3,154.00 (2,833.55 to 3,507.51) 0.11 (0.08 to 0.18) <0.001 Severe vision loss Global 14,674,808.18 (12,674,254.70 to 16,643,542.52) 371.57 (321.03 to 425.03) 29,322,778.59 (25,295,617.43 to 33,665,601.92) 344.89 (298.68 to 394.13) −0.23 (−0.24 to −0.21) <0.001 Gender Male 6,339,317.68 (5,455,492.34 to 7,209,376.64) 354.51 (306.16 to 407.28) 12,420,630.97 (10,673,867.68 to 14,251,102.73) 315.10 (271.75 to 360.56) −0.02 (−0.07 to 0.03) 0.393 Female 8,335,490.50 (7,221,732.71 to 9,489,807.71) 387.86 (335.39 to 441.84) 16,902,147.62 (14,648,583.63 to 19,364,352.82) 371.52 (322.33 to 423.88) −0.36 (−0.45 to −0.23) <0.001 Blindness Global 23,583,876.17 (20,959,315.68 to 26,367,301.16) 609.60 (541.58 to 680.32) 34,201,240.95 (30,203,837.18 to 38,692,045.98) 404.70 (357.67 to 457.32) −1.27 (−1.31 to −1.25) <0.001 Gender Male 10,883,570.72 (9,641,278.88 to 12,214,683.56) 626.42 (555.60 to 701.32) 15,213,446.12 (13,374,059.35 to 17,292,534.37) 391.88 (344.98 to 443.56) −1.47 (−1.59 to −1.17) <0.001 Female 12,700,305.45 (11,302,838.85 to 14,160,846.20) 599.29 (532.39 to 669.00) 18,987,794.84 (16,674,852.41 to 21,516,353.29) 414.82 (364.87 to 469.04) −1.14 (−1.61 to −0.96) <0.001 YLDs (years lived with disability) Moderate vision loss Global 3,894,802.21 (2,392,291.95 to 6,078,714.53) 89.00 (54.85 to 138.40) 7,608,597.78 (4,675,952.39 to 11,797,132.26) 90.55 (55.77 to 140.55) 0.07 (0.06 to 0.08) 0.001 Gender Male 1,771,674.80 (1,085,971.69 to 2,760,290.72) 85.23 (52.52 to 132.62) 3,410,918.69 (2,085,451.10 to 5,291,631.30) 85.33 (52.50 to 132.52) 0.02 (0.00 to 0.08) <0.001 Female 2,123,127.41 (1,309,010.19 to 3,309,770.04) 92.61 (57.07 to 143.92) 4,197,679.10 (2,584,082.89 to 6,505,887.91) 95.45 (58.82 to 148.09) 0.11 (0.06 to 0.18) 0.048 Severe vision loss Global 2,596,940.82 (1,812,719.55 to 3,739,044.50) 65.51 (45.82 to 94.23) 5,187,956.49 (3,627,606.13 to 7,479,108.98) 60.99 (42.70 to 87.84) −0.22 (−0.23 to −0.20) <0.001 Gender Male 1,125,157.33 (781,687.93 to 1,617,532.61) 62.51 (43.67 to 89.84) 2,205,271.19 (1,540,136.90 to 3,172,456.31) 55.82 (39.03 to 80.56) −0.35 (−0.47 to 0.04) 0.49 Female 1,471,783.50 (1,027,586.05 to 2,120,623.81) 68.35 (47.86 to 98.36) 2,982,685.30 (2,089,780.34 to 4,288,763.05) 65.61 (46.00 to 94.27) −0.11 (−0.30 to −0.02) <0.001 Blindness Global 4,245,400.12 (2,879,475.59 to 5,884,309.09) 109.26 (74.33 to 151.40) 6,151,452.63 (4,165,078.63 to 8,558,535.82) 72.74 (49.34 to 100.84) −1.25 (−1.31 to −1.22) <0.001 Gender Male 1,965,866.76 (1,322,604.09 to 2,736,970.04) 112.30 (76.40 to 155.51) 2,747,469.25 (1,848,370.86 to 3,830,767.52) 70.58 (47.58 to 98.14) −1.46 (−1.88 to −1.17) <0.001 Female 2,279,533.36 (1,551,810.54 to 3,163,909.42) 107.32 (72.99 to 149.18) 3,403,983.38 (2,301,472.04 to 4,734,106.07) 74.42 (50.46 to 103.48) −1.11 (−1.60 to −0.50) <0.001 Trend analysis results for the prevalence and YLDs indicators by gender subgroups across different severity levels of vision impairment. AAPC: Average annual percent change; ASR: Age-standardized rate; CI: Confidence interval; UI: Uncertain interval; YLDs: Years lived with disability. From 1990 to 2021, India and China consistently ranked the first and second in YLDs from moderate vision loss, severe vision loss, and blindness. In 2021, the top five countries for moderate vision loss were India, China, Brazil, the Russian Federation, and Pakistan. Among them, China had the highest increase in prevalence (AAPC: 2.31%), while Pakistan saw a slight decrease (AAPC: −0.06%). For severe vision loss, the top five were India, China, Indonesia, Pakistan, and Brazil, with China again showing the highest increase (AAPC: 2.47%) and Pakistan the largest decline (AAPC: −0.57%). For blindness, the leading countries were India, China, and Pakistan; China had the greatest increase (AAPC: 1.13%), whereas India and Indonesia showed notable decreases (AAPCs: −0.91% and −0.11%). Detailed trends are shown in Supplementary Figures 2–4, https://links.lww.com/CM9/C809. In 2021, refractive disorders were the leading cause of moderate vision loss in youth, accounting for over 96% of cases in the 15–19-year age group, but their impact declined with severity. In contrast, glaucoma became a key cause of blindness in the elderly, responsible for 18.0% of cases in females and 26.9% in males aged 95 years and above Supplementary Figure 5, https://links.lww.com/CM9/C809. Females had higher prevalence and YLDs than males across all ages, with most cases concentrated in those aged 60–80 years. Both prevalence and YLDs increased with age Supplementary Figure 6, https://links.lww.com/CM9/C809. We analyzed the correlation between SDI and the ASDR for different levels of vision impairment globally, across 21 regions (1990–2021), and in 204 countries (2021). Results showed a significant negative correlation: globally, R = −0.60 for moderate vision loss, −0.67 for severe vision loss, and −0.85 for blindness (all P <0.001; Supplementary Figure 7A, https://links.lww.com/CM9/C809). Similar trends were observed across countries in 2021 (R = −0.22, −0.46, and −0.73, respectively; Supplementary Figure 7B, https://links.lww.com/CM9/C809). Health inequality analysis further revealed a clear poverty-disease pattern, with more severe vision loss increasingly concentrated in lower SDI settings. In 2021, slope indices were −23.36, −43.05, and −117.67, and concentration indices were −0.12, −0.21, and −0.25 for moderate vision loss, severe vision loss, and blindness, respectively. This pattern was confirmed across global and SDI regions, with the highest burden in low and low-middle SDI areas Supplementary Figures 8 and 9, https://links.lww.com/CM9/C809. Joinpoint trend analysis from 1990 to 2021 showed a slight increase in both ASPR and ASDR for moderate vision loss (AAPC: 0.07; P <0.001), while rates for severe vision loss and blindness declined (ASPR AAPCs: −0.23 and −1.27; ASDR AAPCs: −0.22 and −1.25; all P <0.001) Supplementary Figure 10, https://links.lww.com/CM9/C809. Gender-specific trends are shown in Supplementary Figure 11, https://links.lww.com/CM9/C809. Using the BAPC model, we projected that by 2050, moderate vision loss will affect 411.7 million people, severe vision loss 47.1 million, and blindness 53.2 million. Corresponding YLDs are estimated at 12.5, 8.2, and 9.6 million, respectively. Detailed projections, including UIs and cause-specific trends, are provided in Supplementary Figures 12 and 13 and Supplementary Table 4, https://links.lww.com/CM9/C809. This study provides a comprehensive epidemiological analysis of vision impairment using GBD 2021 data, revealing that while global blindness and severe vision loss have declined since 1990, moderate vision loss is on the rise. Geographically, Côte d’Ivoire and the Northern Mariana Islands exhibited the fastest growth in prevalence, with Western and Central Sub-Saharan Africa facing increasing regional burdens, contrasted by notable declines in South Asia. Among high-burden nations, China, Thailand, and Japan showed rapid growth in moderate loss, severe loss, and blindness, respectively. The analysis indicates that as severity increases, the primary causes shift from refractive disorders to more complex conditions such as glaucoma, cataracts, and AMD. Demographic data show that burden peaks between ages 60–80 and disproportionately affects females due to socioeconomic inequities. Furthermore, a strong negative correlation with the Socio-Demographic Index (SDI) highlights significant health disparities in low-resource settings. Despite a projected decline in age-standardized rates by 2050, total cases are expected to rise, driven by aging populations. Compared to previous GBD research, this study offers novel insights detailed in Supplementary Table 5 https://links.lww.com/CM9/C809. While limited by the reliance on national-level estimates and hierarchical modeling, these findings underscore the urgent need for targeted policies, improved surgical access, and gender-equitable eye care to mitigate the growing global burden of vision impairment.3 Acknowledgments This manuscript was produced as part of the GBD Collaborator Network and in accordance with the GBD protocol. Funding This work was supported by grants from the National Natural Science Foundation of China (No. 82271054), and Natural Science Foundation of Fujian (No. 2023J01012), the China Postdoctoral Science Foundation (No. 2023M741608), the Natural Science Foundation of Hunan Province (No. 2024JJ6402) and the National Natural Science Foundation of China (No. 82401321). Conflicts of interest None.