Virtual reality simulation and real-life training programs for cataract surgery: a scoping review of the literature.

BACKGROUND: Cataract surgery requires a high level of dexterity and experience to avoid serious intra- and post-operative complications. Proper surgical training and evaluation during the learning phase are crucial to promote safety in the operating room (OR). This scoping review aims to report cataract surgery training efficacy for patient safety and trainee satisfaction in the OR when using virtual reality simulators (EyeSi [Haag-Streit, Heidelberg, Germany] or HelpMeSee [HelpMeSee foundation, Jersey city, New Jersey, United States]) or supervised surgical training on actual patients programs in residents. METHODS: An online article search in the PubMed database was performed to identify studies proposing OR performance assessment after virtual-reality simulation (EyeSi or HelpMeSee) or supervised surgical training on actual patients programs. Outcome assessment was primarily based on patient safety (i.e., intra- and post- operative complications, OR performance, operating time) and secondarily based on trainee satisfaction (i.e., subjective assessment). RESULTS: We reviewed 18 articles, involving 1515 participants. There were 13 using the EyeSi simulator, with 10 studies conducted in high-income countries (59%). One study used the HelpMeSee simulator and was conducted in India. The four remaining studies reported supervised surgical training on actual patients, mostly conducted in low- middle- income countries. Training programs greatly differed between studies and the level of certainty was considered low. Only four studies were randomized clinical trials. There were 17 studies (94%) proposing patient safety assessments, mainly through intraoperative complication reports (67%). Significant safety improvements were found in 80% of comparative virtual reality simulation studies. All three supervised surgery studies were observational and reported a high amount of cataract surgeries performed by trainees. However, intraoperative complication rates appeared to be higher than in virtual reality simulation studies. Trainee satisfaction was rarely assessed (17%) and did not correlate with training outcomes. CONCLUSIONS: Patient safety assessment in the OR remains a major concern when evaluating the efficacy of a training program. Virtual reality simulation appears to lead to safer outcomes compared to that of supervised surgical training on actual patients alone, which encourages its use prior to performing real cases. However, actual training programs need to be more consistent, while maintaining a balance between financial, cultural, geographical, and accessibility factors.

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.

A large-scale analysis of refractive errors in students attending public primary schools in Mexico.

A cross-sectional, retrospective study was conducted from September 2013 through July 2014 to determine the prevalence of refractive errors among students attending public primary schools in Mexico. Among 3,861,156 students at 14,566 public primary schools in all 32 states of Mexico, teachers identified reduced visual acuity in 1,253,589 (32.5%) using visual acuity measurement. Optometrists confirmed 391,498 [31.2%, mean (SD) age: 8.8 (1.9) years; 204,110 girls (52.9%)] had refractive errors using visual acuity measurement and noncycloplegic static retinoscopy. Among 288,537 (72.4%) of children with previous eyeglasses usage data reported, 241,505 (83.7%) had uncorrected refractive errors. Before prescription eyeglasses were provided, 281,891 students (72%) had logMAR visual acuity ≤ 0.2; eyeglasses corrected vision loss in 85.6% (n = 241,352) of them. Simple myopic astigmatism was the most frequent refractive error (25.7%, n = 100,545). Astigmatism > - 1.00 diopters was present in 54.6% of all students with ametropia. The anisometropia rate based on spherical equivalent difference between right and left eye ≥ 1.50 diopters was 3.9% (n = 15,402). Uncorrected refractive errors are an important issue in primary school students in Mexico. An updated study is needed to analyze the evolving trends over the past decade.

Estimating mortality and disability in Peru before the COVID-19 pandemic: a systematic analysis from the Global Burden of the Disease Study 2019.

Background: Estimating and analyzing trends and patterns of health loss are essential to promote efficient resource allocation and improve Peru's healthcare system performance. Methods: Using estimates from the Global Burden of Disease (GBD), Injuries, and Risk Factors Study (2019), we assessed mortality and disability in Peru from 1990 to 2019. We report demographic and epidemiologic trends in terms of population, life expectancy at birth (LE), mortality, incidence, prevalence, years of life lost (YLLs), years lived with disability (YLDs), and disability-adjusted life-years (DALYs) caused by the major diseases and risk factors in Peru. Finally, we compared Peru with 16 countries in the Latin American (LA) region. Results: The Peruvian population reached 33.9 million inhabitants (49.9% women) in 2019. From 1990 to 2019, LE at birth increased from 69.2 (95% uncertainty interval 67.8-70.3) to 80.3 (77.2-83.2) years. This increase was driven by the decline in under-5 mortality (-80.7%) and mortality from infectious diseases in older age groups (+60 years old). The number of DALYs in 1990 was 9.2 million (8.5-10.1) and reached 7.5 million (6.1-9.0) in 2019. The proportion of DALYs due to non-communicable diseases (NCDs) increased from 38.2% in 1990 to 67.9% in 2019. The all-ages and age-standardized DALYs rates and YLLs rates decreased, but YLDs rates remained constant. In 2019, the leading causes of DALYs were neonatal disorders, lower respiratory infections (LRIs), ischemic heart disease, road injuries, and low back pain. The leading risk factors associated with DALYs in 2019 were undernutrition, high body mass index, high fasting plasma glucose, and air pollution. Before the COVID-19 pandemic, Peru experienced one of the highest LRIs-DALYs rates in the LA region. Conclusion: In the last three decades, Peru experienced significant improvements in LE and child survival and an increase in the burden of NCDs and associated disability. The Peruvian healthcare system must be redesigned to respond to this epidemiological transition. The new design should aim to reduce premature deaths and maintain healthy longevity, focusing on effective coverage and treatment of NCDs and reducing and managing the related disability.

Preventable risk factors for type 2 diabetes can be detected using noninvasive spontaneous electroretinogram signals.

Given the ever-increasing prevalence of type 2 diabetes and obesity, the pressure on global healthcare is expected to be colossal, especially in terms of blindness. Electroretinogram (ERG) has long been perceived as a first-use technique for diagnosing eye diseases, and some studies suggested its use for preventable risk factors of type 2 diabetes and thereby diabetic retinopathy (DR). Here, we show that in a non-evoked mode, ERG signals contain spontaneous oscillations that predict disease cases in rodent models of obesity and in people with overweight, obesity, and metabolic syndrome but not yet diabetes, using one single random forest-based model. Classification performance was both internally and externally validated, and correlation analysis showed that the spontaneous oscillations of the non-evoked ERG are altered before oscillatory potentials, which are the current gold-standard for early DR. Principal component and discriminant analysis suggested that the slow frequency (0.4-0.7 Hz) components are the main discriminators for our predictive model. In addition, we established that the optimal conditions to record these informative signals, are 5-minute duration recordings under daylight conditions, using any ERG sensors, including ones working with portative, non-mydriatic devices. Our study provides an early warning system with promising applications for prevention, monitoring and even the development of new therapies against type 2 diabetes.

Assessment of a high-fidelity, virtual reality-based, manual small-incision cataract surgery simulator: A face and content validity study.

Purpose: To establish the face and content validity of the HelpMeSee Eye Surgery Simulator - a virtual reality-based cataract surgery simulator for manual small-incision cataract surgery (MSICS). Methods: The face and content validity were assessed on the sclero-corneal tunnel construction course. A questionnaire with 11 questions focused on the visual realism, with resemblance to real life surgery, and the training value of the simulator was developed. Thirty-five experienced MSICS surgeons participated in the study. Responses were recorded using a seven-point scoring system. Results: Overall, 74.3% (26/35) of the respondents agreed that the overall visual representation of the eye and the instruments in the simulator were realistic. The task of injecting a visco-elastic through the paracentesis was reported to be the most visually realistic task with a mean score of 5.78 (SD: 1.09; range: 2-7). With regard to content validity, 77.1% (27/35) of the subjects felt agreed that the errors and complications represented throughout the entire tunnel construction module were similar to those encountered in real life; the task of entering the anterior chamber with the keratome had a mean score of 5.54 (SD: 0.98; range 1-7), being rated the highest in that aspect. Overall, 94.3% (33/35) of the subjects agreed that the simulator would be useful in developing hand-eye co-ordination. A similar number of 94.3% (33/35) agreed that based on their experience, they would recommend cataract surgical training on this simulator. Conclusion: The results suggest that the HelpMeSee Eye Surgery Simulator appears to have sufficient face and content validity for cataract surgical training.

An objective evaluation of simulated surgical outcomes among surgical trainees using manual small-incision cataract surgery virtual reality simulator.

Purpose: The purpose of this study was to evaluate trainee performance across six modules of a virtual reality (VR) simulator. Methods: A retrospective observational study was conducted on 10 manual small-incision cataract surgery (MSICS) trainees who practiced cataract surgery on an MSICS VR simulator for one month. They were assessed in six major steps which included scleral groove, tunnel dissection, keratome entry, capsulorhexis, nucleus delivery, and intraocular lens (IOL) insertion under a trainer's supervision. The information included in their score metrics was collected, and their overall performance was evaluated. Results: Thirty attempts were evaluated for scleral groove, tunnel dissection, and capsulorhexis and 15 attempts for keratome entry. Candidates had varied results in the dimensional aspects and their rates of complications with a mean satisfactory score of 3.1 ± 4.17, 6.8 ± 5.75, 5.8 ± 7.74, and 1.8 ± 2.57, respectively. Nucleus delivery (n = 5) had more of iris pull and IOL insertion (n = 5) had more of lost IOL as complications but both had a higher satisfactory outcome. Conclusion: A VR simulator is a useful tool for training surgeons before their entry into live surgery. It is an effective method for evaluating objectively the structural characteristics of each phase in MSICS and their associated complications, helping them anticipate it earlier during live surgery by giving them a near real world experience.

Wikipedia, friend or foe regarding information on diabetic retinopathy? A content analysis in the world's leading 19 languages.

OBJECTIVE: To compare the completeness and quality of information about diabetic retinopathy on Wikipedia in the world's leading spoken languages in 2020. DESIGN AND METHODS: An observational, descriptive, cross-sectional study. The information on diabetic retinopathy obtained from the free encyclopedia Wikipedia® was assessed in languages with one hundred million or more total speakers. The term "diabetic retinopathy" was accessed in the corresponding Wikipedia entry in English, while the "more languages" function gives access to other languages. The information on the sites was collected by three ophthalmologist observers. A database was created with the most important subtopics for the education of patients with diabetic retinopathy in any of its classifications, based on a 25-question survey. The results were stratified on a scale from 0 to 4. A confirming correlation was found in the statistical analysis among the observers. RESULTS: No language achieved the label "excellent"; 2 languages were rated as "fair "; 4 languages qualified as "substandard"; and 7 languages were scored as "poor." No information could be found in five languages. CONCLUSIONS: As would be expected, the quality of content is variable across different languages. However, if anyone can edit Wikipedia, health professionals can do so as well to improve the quality and quantity of information for patients.

Effectiveness of simulation-based training for manual small incision cataract surgery among novice surgeons: a randomized controlled trial.

This study was designed to determine the effect of a novel simulation-based training curriculum for scleral tunnel construction in manual small incision cataract surgery (MSICS) compared with traditional training. In this multicenter, investigator-masked, randomized clinical trial, resident surgeons within 3 months of matriculation with minimal or no prior experience with MSICS were assigned either to simulation-based training, the Experimental Group (EG), or to conventional training, the Control Group (CG). EG residents were trained to perform scleral tunnel construction using a simulation-based curriculum (HelpMeSee Eye Surgery Simulator), while residents in the CG followed institution-specific curriculum before progressing to live surgery. Surgical videos of the first 20 attempts at tunnel construction were reviewed by masked video raters. The primary outcome was the total number of any of 9 pre-specified errors. On average, the total number of errors was 9.25 (95% CI 0-18.95) in the EG and 17.56 (95% CI 6.63-28.49) in the CG (P = 0.05); the number of major errors was 4.86 (95% CI 0.13-9.59) in the EG and 10.09 (95% CI 4.76-15.41) in the CG (P = 0.02); and the number of minor errors was 4.39 (95% CI 0-9.75) in the EG and 7.47 (95% CI 1.43-13.51) in the CG (P = 0.16). These results support that novice surgeons trained using the novel simulation-based curriculum performed fewer errors in their first 20 attempts at tunnel construction compared to those trained with a conventional curriculum.

Central Macular Thickness in a Healthy Mexican Population Using Huvitz Optical Coherence Tomography.

OBJECTIVE: To determine normal macular thickness values in a healthy Mexican population and its variation by age and gender using Huvitz spectral-domain optical coherence tomography (HOCT-1F). METHODS: This cross-sectional study included 211 consecutive eyes from clinically normal subjects (66 men, 145 women) between October 2018 and December 2018, with best-corrected visual acuities better than 20/30. One eye was selected for the macular scan using the Huvitz OCT (Huvitz OCT-1F, HOCT-1F, Huvitz Co., Ltd., Republic of Korea) with an automated segmentation algorithm. Three vertical and horizontal scans, centered on the fovea with an area of 9 mm, and a color 45° fundus photograph were obtained using Huvitz OCT-1F. Macular measurements were presented as means with standard deviations values for each of the nine regions defined by the Early Treatment Diabetic Retinopathy Study (ETDRS). RESULTS: The mean age was 34.3±11.9 years. Using the ETDRS map, the mean central subfield thickness (CST) was 227.4±18.9 µm. Male gender was associated with greater CST (P<0.001) compared to females. There was no association between mean macular CST (r2=0.011; P=0.11) and age. Macular thickness was thicker in the inner ring than in the outer ring, and there were no significant differences in mean CST among age groups (P=0.70). CONCLUSION: Normal macular thickness values using the Huvitz OCT in a Mexican healthy population aged from 18-70 years were thinner in the foveal macular region than values reported in other populations. Female patients had a thinner CST, and age was not correlated with macular thickness.

Estimated number of ophthalmologists worldwide (International Council of Ophthalmology update): will we meet the needs?

BACKGROUND/AIMS: To estimate 2015 global ophthalmologist data and analyse their relationship to income groups, prevalence rates of blindness and visual impairment and gross domestic product (GDP) per capita. METHODS: Online surveys were emailed to presidents/chairpersons of national societies of ophthalmology and Ministry of Health representatives from all 194 countries to capture the number and density (per million population) of ophthalmologists, the number/density performing cataract surgery and refraction, and annual ophthalmologist population growth trends. Correlations between these data and income group, GDP per capita and prevalence rates of blindness and visual impairment were analysed. RESULTS: In 2015, there were an estimated 232 866 ophthalmologists in 194 countries. Income was positively associated with ophthalmologist density (a mean 3.7 per million population in low-income countries vs a mean 76.2 in high-income countries). Most countries reported positive growth (94/156; 60.3%). There was a weak, inverse correlation between the prevalence of blindness and the ophthalmologist density. There were weak, positive correlations between the density of ophthalmologists performing cataract surgery and GDP per capita and the prevalence of blindness, as well as between GDP per capita and the density of ophthalmologists doing refractions. CONCLUSIONS: Although the estimated global ophthalmologist workforce appears to be growing, the appropriate distribution of the eye care workforce and the development of comprehensive eye care delivery systems are needed to ensure that eye care needs are universally met.

Prevalence and causes of vision loss in Latin America and the Caribbean in 2015: magnitude, temporal trends and projections.

OBJECTIVE: To estimate the prevalence and causes of blindness and vision impairment for distance and near in Latin America and the Caribbean (LAC) in 2015 and to forecast trends to 2020. METHODS: A meta-analysis from a global systematic review of 283 cross-sectional, population-representative studies from published and unpublished sources from 1980 to 2014 in the Global Vision Database included 17 published and 6 unpublished studies from LAC. RESULTS: In 2015, across LAC, age-standardised prevalence was 0.38% in all ages and 1.56% in those over age 50 for blindness; 2.06% in all ages and 7.86% in those over age 50 for moderate and severe vision impairment (MSVI); 1.89% in all ages and 6.93% in those over age 50 for mild vision impairment and 39.59% in all ages and 45.27% in those over 50 for near vision impairment (NVI). In 2015, 117.86 million persons were vision impaired; of those 2.34 million blind, 12.46 million with MSVI, 11.34 million mildly impaired and 91.72 million had NVI. Cataract is the most common cause of blindness. Undercorrected refractive-error is the most common cause of vision impairment. CONCLUSIONS: These prevalence estimates indicate that one in five persons across LAC had some degree of vision loss in 2015. We predict that from 2015 to 2020, the absolute numbers of persons with vision loss will increase by 12% to 132.33 million, while the all-age age-standardised prevalence will decrease for blindness by 15% and for other distance vision impairment by 8%. All countries need epidemiologic research to establish accurate national estimates and trends. Universal eye health services must be included in universal health coverage reforms to address disparities, fragmentation and segmentation of healthcare.

Rapid assessment of avoidable blindness: Prevalence of blindness, visual impairment and diabetes in nuevo leon, Mexico 2014.

PURPOSE: To estimate the prevalence of blindness, visual impairment, diabetes mellitus, and diabetic retinopathy in patients aged 50 years and older in the State of Nuevo León, Mexico. METHODS: Ninety-one clusters of 60 people aged 50+ were selected randomly and a rapid assessment of avoidable blindness (RAAB) was conducted. Participants had their visual acuity and cause of visual impairment assessed, underwent a random glucose test and fundoscopy under mydriasis if they had diabetes. The diabetic retinopathy (DR) degree was classified according to the Scottish diabetic retinopathy grading scheme. RESULTS: From the sample 5,055 (92.6%) people were examined. The blindness prevalence was 1.7% (95% Confidence Interval: 1.3-2.1%). Cataract (32.6%), DR (29.1%) and glaucoma (16.3%) were the leading causes of blindness. The prevalence of severe, moderate, and early visual impairment was 1.0%, 5.1%, and 7.7%, respectively. Among respondents, 31% had diabetes and 8.1% of them was not diagnosed prior to the study. Of all participants with diabetes, 50% had glucose levels of 200 mg/dl or higher and 15.7% had sight-threatening diabetic retinopathy. CONCLUSIONS: Besides strengthening of cataract intervention activities, more ophthalmic services for diabetic retinopathy and glaucoma control are needed in Nuevo León to provide timely intervention to prevent blindness.

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.

Analysis of ophthalmological and vision-related publications in Latin America.

PURPOSE: To assess scientific production related to ophthalmology and vision in Latin America during the period from 2006 to 2015. METHODS: The PubMed, Lilacs (Bireme), Google Scholar, SciELO, and Medigraphic databases were evaluated for this retrospective, descriptive, and comparative study. RESULTS: A total of 1,510 articles was identified. Brazil was the leader in quantitative production in ophthalmology, averaging 85.4 articles per year. Mexico was in second place with 27.4, and Argentina was in third place with 11.1 articles per year. Forty-one percent of articles were published in English, 28.1% dealt with the subspecialty of the retina, and 63% were published by researchers affiliated with universities. The frequency of male first authors was 58.9%, and the journal Arquivos Brasileiros de Oftalmologia accounted for 36.42% of the identified articles. CONCLUSIONS: Brazil stands in first place in Latin America in ophthalmologic scientific production. Nearly half of the researchers in ophthalmology in Latin America included in our study were listed in databases other than PubMed.

Analysis of ophthalmological and vision-related publications in Latin America / Análise de publicações oftalmológicas e relacionadas à visão na América Latina

ABSTRACT Purpose: To assess scientific production related to ophthalmology and vision in Latin America during the period from 2006 to 2015. Methods: The PubMed, Lilacs (Bireme), Google Scholar, SciELO, and Medigraphic databases were evaluated for this retrospective, descriptive, and comparative study. Results: A total of 1,510 articles was identified. Brazil was the leader in quantitative production in ophthalmology, averaging 85.4 articles per year. Mexico was in second place with 27.4, and Argentina was in third place with 11.1 articles per year. Forty-one percent of articles were published in English, 28.1% dealt with the subspecialty of the retina, and 63% were published by researchers affiliated with universities. The frequency of male first authors was 58.9%, and the journal Arquivos Brasileiros de Oftalmologia accounted for 36.42% of the identified articles. Conclusions: Brazil stands in first place in Latin America in ophthalmologic scientific production. Nearly half of the researchers in ophthalmology in Latin America included in our study were listed in databases other than PubMed.

RESUMO Objetivo: Avaliar a produção científica relacionada à oftalmologia e à visão na América Latina durante o período de 2006 a 2015. Métodos: As bases de dados PubMed, Lilacs (Bireme), Google Scholar, SciELO e Medigraphic foram utilizadas para realizar um estudo retrospectivo, descritivo e comparativo. Resultados: Foram identificados 1,510 artigos, sendo que o Brasil foi a principal fonte de produção quantitativa, com uma média de 85,4 artigos por ano; o México aparece em segundo lugar com 27,4 e a Argentina em terceiro lugar com 11,1 artigos por ano. Quarenta e um por cento dos artigos foram publicados em inglês; 28,1% trataram da subespecialidade da retina; e a principal fonte institucional de publicações foram as universidades, com 63%. A frequência de primeiros autores do sexo masculino foi de 58,9%, e a revista Arquivos Brasileiros de Oftalmologia representou 36,42% dos artigos identificados. Conclusões: O Brasil ocupa o primeiro lugar na América Latina na produção científica oftalmológica. Os bancos de dados não indexados no PubMed foram incluídos em nosso estudo, representam quase metade dos pesquisadores em oftalmologia na América Latina.

Cataract Surgical Rate and Socioeconomics: A Global Study.

PURPOSE: Cataract is the leading cause of blindness and cataract surgical rate (CSR) is used as a proxy indicator of access to cataract services in a country. The aim of this study was to explore the associations between the CSR and the economic development of countries in terms of gross domestic product per capital (GDP/P) and gross national income per capita (GNI/P). METHODS: We systematically searched OVID (Medline and Embase), Pubmed, Embase.com, ISI Web of Science, and Cochrane Library databases, and retrieved additional data from unpublished reports. Cataract surgical rates and economic indicators (GDP/P, GNI/P) were collected for each country from 2005 to 2014. Complete data were used for the 50 largest countries according to World Health Organization (WHO) population estimates. Linear correlations between GDP/P and CSR were calculated. Cataract surgical rate data over two periods were used for analysis: 2005 to 2009 and 2010 to 2014 (CSR in 2009 or nearest year, CSR in 2014 or nearest year). RESULTS: Over the study period, CSR data were available for 152 countries across both time periods. Most of the CSR data were obtained from nongovernment organization (NGO) reports, including WHO reports. A good linear correlation between CSR and GDP/P was found overall, nearest to 2009 (ß = 0.162, Linear: y = 0.162x + 282.242; R2 = 0.665, P < 0.001). Regression analysis of CSR nearest to 2014 produced similar findings, with significant correlations between CSR and GDP/P (Linear: y = 0.208x + 94.008; R2 = 0.785, P < 0.001). When using GNI/P as an economic indicator, similarly excellent lines of fit were obtained. After adjusting for time and country, CSR was significantly associated with GDP/P (Coefficient = 0.147, R2 = 0.759, P < 0.001), and GNI/P (Coefficient = 0.152, R2 = 0.757, P < 0.001). Most countries had an increase in CSRs over time, with the greatest increases observed for Iran and Argentina. CONCLUSION: Cataract surgical rate and economic indicators are closely associated, indicating the strong influence of resource availability on healthcare delivery. Considering this relationship, it is important to be innovative in delivery of low-cost services and invest strategically in capacity development to meet cataract surgical need in low-resource settings.

Trachoma.

INTRODUCTION: Active trachoma is caused by chronic infection of the conjunctiva by Chlamydia trachomatis, and is the world's leading infectious cause of blindness. Infection can lead to: scarring of the tarsal conjunctiva; inversion of the eyelashes (trichiasis), so that they abrade the cornea; and corneal opacity, resulting in blindness. Trachoma is a disease of poverty, overcrowding, and poor sanitation. Active disease affects mainly children, but adults are at increased risk of scarring. METHODS AND OUTCOMES: We conducted a systematic overview, aiming to answer the following clinical question: What are the effects of interventions to prevent scarring trachoma by reducing the prevalence of active trachoma? We searched: Medline, Embase, The Cochrane Library and other important databases up to December 2014 (Clinical Evidence overviews are updated periodically; please check our website for the most up-to-date version of this overview). RESULTS: At this update, searching of electronic databases retrieved 170 studies. After deduplication and removal of conference abstracts, 96 records were screened for inclusion in the overview. Appraisal of titles and abstracts led to the exclusion of 61 studies and the further review of 35 full publications. Of the 35 full articles evaluated, three previously included systematic reviews were updated, one systematic review and two RCTs were added at this update, and two RCTs and one further report were added the Comment sections. We performed a GRADE evaluation for nine PICO combinations. CONCLUSIONS: In this systematic overview, we categorised the efficacy for seven interventions based on information about the effectiveness and safety of antibiotics, face washing (alone or plus topical tetracycline), fly control (through the provision of pit latrines, and using insecticide alone or plus antibiotics), and health education.