Global Trends in Blindness and Vision Impairment Resulting from Corneal Opacity 1984-2020: A Meta-analysis.

TOPIC: We provide global estimates of the prevalence of corneal blindness and vision impairment in adults 40 years of age and older and examine the burden by age, sex, and geographic region from 1984 through 2020. CLINICAL RELEVANCE: Corneal opacities (COs) are among the top 5 causes of blindness worldwide, yet the global prevalence, regional differences, and risk factors are unclear. METHODS: Abstracted data from the published literature and surveys were obtained from the Global Burden of Disease Vision Loss Expert Group. We supplemented this by an independent systematic literature search of several databases. Studies that provided CO vision impairment data based on population-based surveys for those 40 years of age or older were included, for a total of 244. For each of the 4 outcomes of blindness and moderate to severe vision impairment (MSVI) caused by trachomatous and nontrachomatous CO (NTCO), time trends and differences in prevalence by region, age, and sex were evaluated using a Poisson log-linear model with a generalized estimating equation method. Age-standardized estimates of global prevalence of blindness and MSVI were calculated using the 2015 United Nations standard populations. RESULTS: The global prevalence of blindness resulting from NTCO in those 40 years and older was 0.081% (95% confidence interval [CI], 0.049%-0.315%); that of MSVI was 0.130% (95% CI, 0.087%-0.372%). A significant increase with age was found (prevalence rate ratio, 2.15; 95% CI, 1.99-2.32). Latin America and Europe showed the lowest rates, with 2- to 8-fold higher rates of blindness or MSVI in other regions. The global prevalence of blindness resulting from trachomatous CO in those 50 years and older was 0.0094% (95% CI, 0%-0.0693%); that from MSVI was 0.012% (95% CI, 0%-0.0761%). Blindness resulting from trachomatous CO and MSVI increased with age and female sex, and rates were significantly higher in the African regions. A decrease in trachomatous blindness rates over time was found (prevalence rate ratio, 0.91; 95% CI, 0.86-0.96). DISCUSSION: An estimated 5.5 million people worldwide are bilaterally blind or have MSVI resulting from CO, with an additional 6.2 million unilaterally blind. Blindness resulting from trachomatous CO is declining over time, likely because of the massive scaleup of the global trachoma elimination program and overall socioeconomic development. FINANCIAL DISCLOSURE(S): The author(s) have no proprietary or commercial interest in any materials discussed in this article.

Improving population-level refractive error monitoring via mixture distributions.

INTRODUCTION: Sampling and describing the distribution of refractive error in populations is critical to understanding eye care needs, refractive differences between groups and factors affecting refractive development. We investigated the ability of mixture models to describe refractive error distributions. METHODS: We used key informants to identify raw refractive error datasets and a systematic search strategy to identify published binned datasets of community-representative refractive error. Mixture models combine various component distributions via weighting to describe an observed distribution. We modelled raw refractive error data with a single-Gaussian (normal) distribution, mixtures of two to six Gaussian distributions and an additive model of an exponential and Gaussian (ex-Gaussian) distribution. We tested the relative fitting accuracy of each method via Bayesian Information Criterion (BIC) and then compared the ability of selected models to predict the observed prevalence of refractive error across a range of cut-points for both the raw and binned refractive data. RESULTS: We obtained large raw refractive error datasets from the United States and Korea. The ability of our models to fit the data improved significantly from a single-Gaussian to a two-Gaussian-component additive model and then remained stable with ≥3-Gaussian-component mixture models. Means and standard deviations for BIC relative to 1 for the single-Gaussian model, where lower is better, were 0.89 ± 0.05, 0.88 ± 0.06, 0.89 ± 0.06, 0.89 ± 0.06 and 0.90 ± 0.06 for two-, three-, four-, five- and six-Gaussian-component models, respectively, tested across US and Korean raw data grouped by age decade. Means and standard deviations for the difference between observed and model-based estimates of refractive error prevalence across a range of cut-points for the raw data were -3.0% ± 6.3, 0.5% ± 1.9, 0.6% ± 1.5 and -1.8% ± 4.0 for one-, two- and three-Gaussian-component and ex-Gaussian models, respectively. CONCLUSIONS: Mixture models appear able to describe the population distribution of refractive error accurately, offering significant advantages over commonly quoted simple summary statistics such as mean, standard deviation and prevalence.

Time Outdoors in Reducing Myopia: A School-Based Cluster Randomized Trial with Objective Monitoring of Outdoor Time and Light Intensity.

PURPOSE: To evaluate the efficacy of time outdoors per school day over 2 years on myopia onset and shift. DESIGN: A prospective, cluster-randomized, examiner-masked, 3-arm trial. PARTICIPANTS: A total of 6295 students aged 6 to 9 years from 24 primary schools in Shanghai, China, stratified and randomized by school in a 1:1:1 ratio to control (n = 2037), test I (n = 2329), or test II (n = 1929) group. METHODS: An additional 40 or 80 minutes of outdoor time was allocated to each school day for test I and II groups. Children in the control group continued their habitual outdoor time. Objective monitoring of outdoor and indoor time and light intensity each day was measured with a wrist-worn wearable during the second-year follow-up. MAIN OUTCOME MEASURES: The 2-year cumulative incidence of myopia (defined as cycloplegic spherical equivalent [SE] of ≤-0.5 diopters [D] in the right eye) among the students without myopia at baseline and changes in SE and axial length (AL) after 2 years. RESULTS: The unadjusted 2-year cumulative incidence of myopia was 24.9%, 20.6%, and 23.8% for control, test I, and II groups, respectively. The adjusted incidence decreased by 16% (incidence risk ratio [IRR], 0.84; 95% confidence interval [CI], 0.72-0.99; P = 0.035) in test I and 11% (IRR = 0.89; 95% CI, 0.79-0.99; P = 0.041) in test II when compared with the control group. The test groups showed less myopic shift and axial elongation compared with the control group (test I: -0.84 D and 0.55 mm, test II: -0.91 D and 0.57 mm, control: -1.04 D and 0.65 mm). There was no significant difference in the adjusted incidence of myopia and myopic shift between the 2 test groups. The test groups had similar outdoor time and light intensity (test I: 127 ± 30 minutes/day and 3557 ± 970 lux/minute; test II: 127 ± 26 minutes/day and 3662 ± 803 lux/minute) but significantly more outdoor time and higher light intensity compared with the control group (106 ± 27 minutes/day and 2984 ± 806 lux/minute). Daily outdoor time of 120 to 150 minutes at 5000 lux/minutes or cumulative outdoor light intensity of 600 000 to 750 000 lux significantly reduced the IRR by 15%～ 24%. CONCLUSIONS: Increasing outdoor time reduced the risk of myopia onset and myopic shifts, especially in nonmyopic children. The protective effect of outdoor time was related to the duration of exposure and light intensity. The dose-response effect between test I and test II was not observed probably because of insufficient outdoor time achieved in the test groups, which suggests that proper monitoring on the compliance on outdoor intervention is critical if one wants to see the protective effect.

Orbital migration of schistosome eggs: a case report.

BACKGROUND: Ocular damage, including damage to the conjunctiva, lacrimal gland, eyelids, and orbit, caused by Schistosoma haematobium is sporadic. We report a clinical case of orbital migration of schistosome eggs. CASE PRESENTATION: A 14-year-old boy of Malian nationality presented with a painless swelling of the upper right eyelid, which had been gradually increasing for approximately 3 months. Visual acuity was logMAR 0.10 and 0.00 in the right and left eye, respectively. External examination revealed a right palpebral mass, pushing the globe slightly downward and inward. Computed tomography revealed a mass of the right lacrimal gland. Total excision of the mass was performed by transpalpebral orbitotomy. Pathological examination revealed an inflammatory granulomatous infiltrate of the lacrimal gland consisting of lymphocytes, eosinophils, giant cells, epithelioid cell, histiocytes and calcified Schistosoma eggs with terminal spine. Urine examination revealed eggs of S. haematobium. Praziquantel 40 mg/kg was administered to the patient. The hematuria stopped after 1 week. After 3 years of follow-up, no recurrence was noted. CONCLUSIONS: The bilharzian granuloma of the lacrimal gland is an ectopic site of the parasite. In this case, the granuloma was cured by surgical excision followed by a course of Praziquantel.

Potential Lost Productivity Resulting from the Global Burden of Myopia: Systematic Review, Meta-analysis, and Modeling.

PURPOSE: We estimated the potential global economic productivity loss resulting from vision impairment (VI) and blindness as a result of uncorrected myopia and myopic macular degeneration (MMD) in 2015. CLINICAL RELEVANCE: Understanding the economic burden of VI associated with myopia is critical to addressing myopia as an increasingly prevalent public health problem. METHODS: We estimated the number of people with myopia and MMD corresponding to critical visual acuity thresholds. Spectacle correction coverage was analyzed against country-level variables from the year of data collection; variation in spectacle correction was described best by a model based on a human development index, with adjustments for urbanization and age. Spectacle correction and myopia data were combined to estimate the number of people with each level of VI resulting from uncorrected myopia. We then applied disability weights, labor force participation rates, employment rates, and gross domestic product per capita to estimate the potential productivity lost among individuals with each level and type of VI resulting from myopia in 2015 in United States dollars (US$). An estimate of care-associated productivity loss also was included. RESULTS: People with myopia are less likely to have adequate optical correction if they are older and live in a rural area of a less developed country. The global potential productivity loss associated with the burden of VI in 2015 was estimated at US$244 billion (95% confidence interval [CI], US$49 billion-US$697 billion) from uncorrected myopia and US$6 billion (95% CI, US$2 billion-US$17 billion) from MMD. Our estimates suggest that the Southeast Asia, South Asia, and East Asia Global Burden of Disease regions bear the greatest potential burden as a proportion of their economic activity, whereas East Asia bears the greatest potential burden in absolute terms. CONCLUSIONS: Even under conservative assumptions, the potential productivity loss associated with VI and blindness resulting from uncorrected myopia is substantially greater than the cost of correcting myopia.

Shanghai Time Outside to Reduce Myopia trial: design and baseline data.

IMPORTANCE: Myopia is a major public health concern worldwide, while outdoor time is indicated to be protective against the onset of myopia. BACKGROUND: To describe the methodology and baseline data of the Shanghai Time Outside to Reduce Myopia (STORM) trial. DESIGN: A 2-year, school-based, prospective, cluster randomized trial. PARTICIPANTS: Children from grade I and II classes of 24 schools from eight districts in Shanghai, China, were randomized to either a control group, a test group I (40-min outdoor time/day) or test group II (80-min outdoor time/day). METHODS: At baseline and annual intervals, cycloplegic autorefraction and axial length measurement will be performed. Time outdoors and light exposure will be monitored via parent/carer questionnaires and a wearable device. MAIN OUTCOME MEASURES: Spherical equivalent, prevalence of myopia and time outdoors in each group. RESULTS: A total of 6295 eligible children (age 7.2 ± 0.7 y [6-9 y]) were randomized to control (n = 2037), test group I (n = 2329) and test group II (n = 1929). At baseline, spherical equivalent was +0.98 ± 1.02D, +1.02 ± 1.02D and +1.00 ± 0.99D (P = 0.708), myopia prevalence was 8.9, 7.7 and 7.8% (P = 0.270) and time outdoors was 58.5 ± 35.8, 59.8 ± 34.7 and 58.5 ± 35.3 min/d (P = 0.886) for control, test groups I and II, respectively. CONCLUSIONS AND RELEVANCE: Myopia prevalence was high at nearly 8 to 9% in school children aged 7 years in Shanghai, China. The current trial will help evaluate if increased time outdoors has a role to play in reducing the incidence of myopia and/or slow the progression of myopia.

Global Prevalence of Presbyopia and Vision Impairment from Uncorrected Presbyopia: Systematic Review, Meta-analysis, and Modelling.

TOPIC: Presbyopia prevalence and spectacle-correction coverage were estimated by systematic review and meta-analysis of epidemiologic evidence, then modeled to expand to country, region, and global estimates. CLINICAL RELEVANCE: Understanding presbyopia epidemiologic factors and correction coverage is critical to overcoming the burden of vision impairment (VI) from uncorrected presbyopia. METHODS: We performed systematic reviews of presbyopia prevalence and spectacle-correction coverage. Accepted presbyopia prevalence data were gathered into 5-year age groups from 0 to 90 years or older and meta-analyzed within World Health Organization global burden of disease regions. We developed a model based on amplitude of accommodation adjusted for myopia rates to match the regionally meta-analyzed presbyopia prevalence. Presbyopia spectacle-correction coverage was analyzed against country-level variables from the year of data collection; variation in correction coverage was described best by a model based on the Human Development Index, Gini coefficient, and health expenditure, with adjustments for age and urbanization. We used the models to estimate presbyopia prevalence and spectacle-correction coverage in each age group in urban and rural areas of every country in the world, and combined with population data to estimate the number of people with near VI. RESULTS: We estimate there were 1.8 billion people (prevalence, 25%; 95% confidence interval [CI], 1.7-2.0 billion [23%-27%]) globally with presbyopia in 2015, 826 million (95% CI, 686-960 million) of whom had near VI because they had no, or inadequate, vision correction. Global unmet need for presbyopia correction in 2015 is estimated to be 45% (95% CI, 41%-49%). People with presbyopia are more likely to have adequate optical correction if they live in an urban area of a more developed country with higher health expenditure and lower inequality. CONCLUSIONS: There is a significant burden of VI from uncorrected presbyopia, with the greatest burden in rural areas of low-resource countries.

Guidelines on Diabetic Eye Care: The International Council of Ophthalmology Recommendations for Screening, Follow-up, Referral, and Treatment Based on Resource Settings.

Diabetes mellitus (DM) is a global epidemic and affects populations in both developing and developed countries, with differing health care and resource levels. Diabetic retinopathy (DR) is a major complication of DM and a leading cause of vision loss in working middle-aged adults. Vision loss from DR can be prevented with broad-level public health strategies, but these need to be tailored to a country's and population's resource setting. Designing DR screening programs, with appropriate and timely referral to facilities with trained eye care professionals, and using cost-effective treatment for vision-threatening levels of DR can prevent vision loss. The International Council of Ophthalmology Guidelines for Diabetic Eye Care 2017 summarize and offer a comprehensive guide for DR screening, referral and follow-up schedules for DR, and appropriate management of vision-threatening DR, including diabetic macular edema (DME) and proliferative DR, for countries with high- and low- or intermediate-resource settings. The guidelines include updated evidence on screening and referral criteria, the minimum requirements for a screening vision and retinal examination, follow-up care, and management of DR and DME, including laser photocoagulation and appropriate use of intravitreal anti-vascular endothelial growth factor inhibitors and, in specific situations, intravitreal corticosteroids. Recommendations for management of DR in patients during pregnancy and with concomitant cataract also are included. The guidelines offer suggestions for monitoring outcomes and indicators of success at a population level.

General analysis of factors influencing cataract surgery practice in Shanghai residents.

BACKGROUND: It was reported that lack of knowledge, less confidence of medical services, commute difficulties, and poor economic conditions would be the main barriers for cataract surgery practice. The influencing factors could have changed in cities with high developing speed. Shanghai is one of the biggest cities in China and the world. The purpose of the study was to explore the factors influencing cataract surgery practice in Shanghai. METHODS: This was a population-based, cross-sectional study. A total of 2342 cataract patients older than 50 years old with cataract-induced visual impairment or who had undergone cataract surgery were recruited from rural and urban areas of Shanghai. Participants accepted a face-to-face structured questionnaire. Data were collected on patient demographics, education, work, income, health insurance, awareness about cataracts disease, treatment and related medical resources and deration policy, transportation and degree of satisfaction with hospitals. RESULTS: There were 417 patients who had received cataract surgery, 404 of them supplied complete information in the questionnaire. More female subjects (64.6%) than male subjects (35.4%) accepted cataract surgery among the 404 patients. Of the patients with cataract history, 36.4% of surgery patients were equal or older than 80. More people with urban medical insurance received surgery (p = 0.036). Patients who received surgery were more satisfied with local medical service (p = 0.032). In urban area, Lower income and difficulties with commutes were related to a higher rate of surgery. CONCLUSIONS: Cataract patients with the following features were more inclined to receive surgery: female, old age, better awareness. In urban areas low income and difficult commutes did not represent barriers for cataract surgery, probably because of appropriate cataract surgery promotion policies recent years in Shanghai. In rural areas, better healthcare reimbursement policies would likely lead to a higher uptake of cataract surgery. Further cohort studies with more controls could supply stronger evidence for our viewpoint.

Design and methodology of the Shanghai child and adolescent large-scale eye study (SCALE).

IMPORTANCE: Nearly half of children suffering vision impairment reside in China with myopia accounting for the vast majority. BACKGROUND: To describe the design and methodology of the Shanghai Child and Adolescent Large-scale Eye Study (SCALE). DESIGN: The SCALE was a city wide, school-based, prospective survey. PARTICIPANTS: Children and adolescents aged 4-14 years from kindergarten (middle and senior), primary schools and junior high schools of all 17 districts and counties of the city of Shanghai, China were examined in 2012-2013. METHODS: Each enrolled child underwent vision assessment (distance visual acuity; uncorrected and with corrective device if worn) and their parent/carer completed a questionnaire designed to elicit risk factors associated with myopia. Additionally, non-cycloplegic autorefraction and ocular axial length was measured in a subset of the larger sample. MAIN OUTCOME MEASURES: Prevalence and the associated factors of vision impairment, myopia and high myopia in Shanghai. RESULTS: In 2012-2013, a total of 910 245 of the eligible 1 196 763 children and adolescents identified from census (76%, mean age 9.0 ± 2.7 years [4-14 years]) were enrolled with visual acuity screened in the city of Shanghai. Of these, 610 952 children (67% of the entire sample) underwent non-cycloplegic autorefraction and 219 188 (24% of the entire sample) had both non-cycloplegic autorefraction and axial length measurements. CONCLUSIONS AND RELEVANCE: The study results will provide insights on the burden of vision impairment, myopia and high myopia in children and adolescents in a metropolitan area of China, and contribute to the policies and strategies to address and limit the burden.

Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050.

PURPOSE: Myopia is a common cause of vision loss, with uncorrected myopia the leading cause of distance vision impairment globally. Individual studies show variations in the prevalence of myopia and high myopia between regions and ethnic groups, and there continues to be uncertainty regarding increasing prevalence of myopia. DESIGN: Systematic review and meta-analysis. METHODS: We performed a systematic review and meta-analysis of the prevalence of myopia and high myopia and estimated temporal trends from 2000 to 2050 using data published since 1995. The primary data were gathered into 5-year age groups from 0 to ≥100, in urban or rural populations in each country, standardized to definitions of myopia of -0.50 diopter (D) or less and of high myopia of -5.00 D or less, projected to the year 2010, then meta-analyzed within Global Burden of Disease (GBD) regions. Any urban or rural age group that lacked data in a GBD region took data from the most similar region. The prevalence data were combined with urbanization data and population data from United Nations Population Department (UNPD) to estimate the prevalence of myopia and high myopia in each country of the world. These estimates were combined with myopia change estimates over time derived from regression analysis of published evidence to project to each decade from 2000 through 2050. RESULTS: We included data from 145 studies covering 2.1 million participants. We estimated 1406 million people with myopia (22.9% of the world population; 95% confidence interval [CI], 932-1932 million [15.2%-31.5%]) and 163 million people with high myopia (2.7% of the world population; 95% CI, 86-387 million [1.4%-6.3%]) in 2000. We predict by 2050 there will be 4758 million people with myopia (49.8% of the world population; 3620-6056 million [95% CI, 43.4%-55.7%]) and 938 million people with high myopia (9.8% of the world population; 479-2104 million [95% CI, 5.7%-19.4%]). CONCLUSIONS: Myopia and high myopia estimates from 2000 to 2050 suggest significant increases in prevalences globally, with implications for planning services, including managing and preventing myopia-related ocular complications and vision loss among almost 1 billion people with high myopia.

Global Vision Impairment and Blindness Due to Uncorrected Refractive Error, 1990-2010.

The purpose of this systematic review was to estimate worldwide the number of people with moderate and severe visual impairment (MSVI; presenting visual acuity <6/18, ≥3/60) or blindness (presenting visual acuity <3/60) due to uncorrected refractive error (URE), to estimate trends in prevalence from 1990 to 2010, and to analyze regional differences. The review focuses on uncorrected refractive error which is now the most common cause of avoidable visual impairment globally. : The systematic review of 14,908 relevant manuscripts from 1990 to 2010 using Medline, Embase, and WHOLIS yielded 243 high-quality, population-based cross-sectional studies which informed a meta-analysis of trends by region. The results showed that in 2010, 6.8 million (95% confidence interval [CI]: 4.7-8.8 million) people were blind (7.9% increase from 1990) and 101.2 million (95% CI: 87.88-125.5 million) vision impaired due to URE (15% increase since 1990), while the global population increased by 30% (1990-2010). The all-age age-standardized prevalence of URE blindness decreased 33% from 0.2% (95% CI: 0.1-0.2%) in 1990 to 0.1% (95% CI: 0.1-0.1%) in 2010, whereas the prevalence of URE MSVI decreased 25% from 2.1% (95% CI: 1.6-2.4%) in 1990 to 1.5% (95% CI: 1.3-1.9%) in 2010. In 2010, URE contributed 20.9% (95% CI: 15.2-25.9%) of all blindness and 52.9% (95% CI: 47.2-57.3%) of all MSVI worldwide. The contribution of URE to all MSVI ranged from 44.2 to 48.1% in all regions except in South Asia which was at 65.4% (95% CI: 62-72%). : We conclude that in 2010, uncorrected refractive error continues as the leading cause of vision impairment and the second leading cause of blindness worldwide, affecting a total of 108 million people or 1 in 90 persons.

The prevention and management of postoperative trachomatous trichiasis: A systematic review.

Among ocular infections, trachoma is the main cause of blindness. Repeated conjunctival Chlamydia trachomatis infections lead to trichiasis, corneal opacification, and visual impairment. Surgery is often needed to relieve discomfort and preserve vision; however, a high postoperative trachomatous trichiasis (PTT) rate has been observed in various settings. We wanted to know why, whether PTT rates could be reduced, and how to manage the PTT that occurs. We performed a search of the literature. Of 217 papers screened, 59 studies were identified for inclusion as potentially relevant, the majority having been excluded for not directly concerning PTT in humans. Preventing PTT is a major challenge. Only one published trial, the STAR trial in Ethiopia, has reported a cumulative PTT rate <10% one year after surgery. The literature on the management of PTT is sparse. Though no PTT management guidelines are available, high-quality surgery with a low rate of unfavorable outcomes for PTT patients is likely to require enhanced training of a smaller group of highly-skilled surgeons. Based on the surgical complexity and the authors' own experience, the pathway for patients suffering from PTT should be studied further for improvement.

Self-reported dual sensory impairment and related factors: a European population-based cross-sectional survey.

BACKGROUND: Data on population-based self-reported dual vision and hearing impairment are sparse in Europe. We aimed to investigate self-reported dual sensory impairment (DSI) in European population. METHODS: A standardised questionnaire was used to collect medical and socio-economic data among individuals aged 15 years or more in 29 European countries. Individuals living in collective households or in institutions were excluded from the survey. RESULTS: Among 296 677 individuals, the survey included 153 866 respondents aged 50 years old or more. The crude prevalence of DSI was of 7.54% (7.36-7.72). Among individuals aged 60 or more, 9.23% of men and 10.94% of women had DSI. Eastern and southern countries had a higher prevalence of DSI. Multivariable analyses showed that social isolation and poor self-rated health status were associated with DSI with ORs of 2.01 (1.77-2.29) and 2.33 (2.15-2.52), while higher income was associated with lower risk of DSI (OR of 0.83 (0.78-0.89). Considering country-level socioeconomic factors, Human Development Index explained almost 38% of the variance of age-adjusted prevalence of DSI. CONCLUSION: There are important differences in terms of prevalence of DSI in Europe, depending on socioeconomic and medical factors. Prevention of DSI does represent an important challenge for maintaining quality of life in elderly population.

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

BACKGROUND: To estimate global and regional trends from 2000 to 2020 of the number of persons visually impaired by cataract and their proportion of the total number of vision-impaired individuals. METHODS: A systematic review and meta-analysis of published population studies and gray literature from 2000 to 2020 was carried out to estimate global and regional trends. We developed prevalence estimates based on modeled distance visual impairment and blindness due to cataract, producing location-, year-, age-, and sex-specific estimates of moderate to severe vision impairment (MSVI presenting visual acuity <6/18, ≥3/60) and blindness (presenting visual acuity <3/60). Estimates are age-standardized using the GBD standard population. RESULTS: In 2020, among overall (all ages) 43.3 million blind and 295 million with MSVI, 17.0 million (39.6%) people were blind and 83.5 million (28.3%) had MSVI due to cataract blind 60% female, MSVI 59% female. From 1990 to 2020, the count of persons blind (MSVI) due to cataract increased by 29.7%(93.1%) whereas the age-standardized global prevalence of cataract-related blindness improved by -27.5% and MSVI increased by 7.2%. The contribution of cataract to the age-standardized prevalence of blindness exceeded the global figure only in South Asia (62.9%) and Southeast Asia and Oceania (47.9%). CONCLUSIONS: The number of people blind and with MSVI due to cataract has risen over the past 30 years, despite a decrease in the age-standardized prevalence of cataract. This indicates that cataract treatment programs have been beneficial, but population growth and aging have outpaced their impact. Growing numbers of cataract blind indicate that more, better-directed, resources are needed to increase global capacity for cataract surgery.

The Better Operative Outcomes Software Tool (BOOST) Prospective Study: Improving the Quality of Cataract Surgery Outcomes in Low-Resource Settings.

PURPOSE: Post-operative vision impairment is common among patients who have undergone cataract surgery in low-resource settings, impacting quality of clinical outcomes and patient experience. This prospective, multisite, single-armed, pragmatic validation study aimed to assess whether receiving tailored recommendations via the free Better Operative Outcomes Software Tool (BOOST) app improved surgical outcomes, as quantified by post-operative unaided distance visual acuity (UVA) measured 1-3 days after surgery. METHODS: During the baseline data collection round, surgeons in low and middle-income countries recorded clinical characteristics of 60 consecutive cataract cases in BOOST. Additional data on the causes of poor outcomes from 20 consecutive cases with post-operative UVA of <6/60 (4-12 weeks post-surgery) were entered to automatically generate tailored recommendations for improvement, before 60 additional consecutive cases were recorded during the follow-up study round. Average UVA was compared between cases recorded in the baseline study round and those recorded during follow-up. RESULTS: Among 4,233 cataract surgeries performed by 41 surgeons in 18 countries, only 2,002 (47.3%) had post-operative UVA 6/12 or better. Among the 14 surgeons (34.1%) who completed both rounds of the study (1,680 cases total), there was no clinically significant improvement in post-operative average UVA (logMAR units ±SD) between baseline (0.50 ± 0.37) and follow-up (0.47 ± 0.36) rounds (mean improvement 0.03, p = 0.486). CONCLUSIONS: Receiving BOOST-generated recommendations did not result in improved UVA beyond what could be expected from prospective monitoring of surgical outcomes alone. Additional research is required to assess whether targeted support to implement changes could potentiate the uptake of app-generated recommendations and improve outcomes.

Global prevalence of vision impairment and blindness: magnitude and temporal trends, 1990-2010.

PURPOSE: Vision impairment is a leading and largely preventable cause of disability worldwide. However, no study of global and regional trends in the prevalence of vision impairment has been carried out. We estimated the prevalence of vision impairment and its changes worldwide for the past 20 years. DESIGN: Systematic review. PARTICIPANTS: A systematic review of published and unpublished population-based data on vision impairment and blindness from 1980 through 2012. METHODS: Hierarchical models were fitted fitted to estimate the prevalence of moderate and severe vision impairment (MSVI; defined as presenting visual acuity <6/18 but ≥ 3/60) and the prevalence of blindness (presenting visual acuity <3/60) by age, country, and year. MAIN OUTCOME MEASURES: Trends in the prevalence of MSVI and blindness for the period 1990 through 2010. RESULTS: Globally, 32.4 million people (95% confidence interval [CI], 29.4-36.5 million people; 60% women) were blind in 2010, and 191 million people (95% CI, 174-230 million people; 57% women) had MSVI. The age-standardized prevalence of blindness in older adults (≥ 50 years) was more than 4% in Western Sub-Saharan Africa (6.0%; 95% CI, 4.6%-7.1%), Eastern Sub-Saharan Africa (5.7%; 95% CI, 4.4%-6.9%), South Asia (4.4%; 95% CI, 3.5%-5.1%), and North Africa and the Middle East (4.6%; 95% CI, 3.5%-5.8%), in contrast to high-income regions with blindness prevalences of ≤ 0.4% or less. The MSVI prevalence in older adults was highest in South Asia (23.6%; 95% CI, 19.4%-29.4%), Oceania (18.9%; 95% CI, 11.8%-23.7%), and Eastern and Western Sub-Saharan Africa and North Africa and the Middle East (95% CI, 15.9%-16.8%). The MSVI prevalence was less than 5% in all 4 high-income regions. The global age-standardized prevalence of blindness and MSVI for older adults decreased from 3.0% (95% CI, 2.7%-3.4%) worldwide in 1990 to 1.9% (95% CI, 1.7%-2.2%) in 2010 and from 14.3% (95% CI, 12.1%-16.2%) worldwide to 10.4% (95% CI, 9.5%-12.3%), respectively. When controlling for age, women's prevalence of blindness was greater than men's in all world regions. Because the global population has increased and aged between 1990 and 2010, the number of blind has increased by 0.6 million people (95% CI, -5.2 to 5.3 million people). The number with MSVI may have increased by 19 million people (95% CI, -8 to 72 million people) from 172 million people (95% CI, 142-198 million people) in 1990. CONCLUSIONS: The age-standardized prevalence of blindness and MSVI has decreased in the past 20 years. However, because of population growth and the relative increase in older adults, the blind population has been stable and the population with MSVI may have increased