Juan Carlos Silva

Independent consultant · Research organizations

BACKGROUND: Uncorrected refractive error (URE) is a readily treatable cause of visual impairment (VI). This study provides updated estimates of global and regional vision loss due to URE, presenting temporal change for VISION 2020 METHODS: Data from population-based eye disease surveys from 1980-2018 were collected. Hierarchical models estimated pr...

Background We aimed to update estimates of global vision loss due to age-related macular degeneration (AMD). Methods We did a systematic review and meta-analysis of population-based surveys of eye diseases from January, 1980, to October, 2018. We fitted hierarchical models to estimate the prevalence of moderate and severe vision impairment (MSVI;...

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...

Background Indigenous peoples experience worse eye health compared to non-Indigenous peoples. Service providers and researchers must avoid perpetuating this inequity. To help achieve this, researchers can use the CONSolIDated critERia for strengthening the reporting of health research involving Indigenous peoples (CONSIDER) statement. This study ai...

Background To estimate global and regional trends from 2000-2020 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 grey literature from 2000-2020 was carried out to estimate global and regio...

The Colombian program to end trachoma implements the component F of the SAFE strategy in the Vaupés department of the Amazon rainforest. Cultural, linguistic, and geographical barriers and the coexistence of an ancestral medical system demand the technical and sociocultural adaptation of this component. A cross-sectional survey combined with focus-...

Vision loss from cataract is unequally distributed, and there is very little evidence on how to overcome this inequity. This project aimed to engage multiple stakeholder groups to identify and prioritise (1) delivery strategies that improve access to cataract services for under-served groups and (2) population groups to target with these strategies...

Review of the burden of vision impairment and blindness and ocular disease occurrence in Indigenous Peoples of the Americas. We systematically reviewed findings of the frequency of vision impairment and blindness and/or frequency of ocular findings in Indigenous groups. The database search yielded 2829 citations, of which 2747 were excluded. We scr...

Background We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods Drawing on methods used in previou...

Background: We undertook a Grand Challenges in Global Eye Health prioritisation exercise to identify the key issues that must be addressed to improve eye health in the context of an ageing population, to eliminate persistent inequities in health-care access, and to mitigate widespread resource limitations. Methods: Drawing on methods used in previ...

Objectives To identify barriers and enablers to accessing school-based eye health programs in Bogotá, Colombia. Methods We undertook a qualitative case study that explored how structural factors, and social and cultural norms influence access to school-based eye health programs. We conducted focus groups discussions and interviews with a purposive...

Purpose To report findings of a telemedicine retinopathy of prematurity (ROP) screening program in six neonatal units in rural areas of Guatemala, using a portable, noncontact, 40° field digital fundus camera (Pictor Plus) operated by trained technicians. Methods National ROP Program Guidelines screening criteria were used: gestational age <36 wee...

The eye care sector is well positioned to contribute to the advancement of universal health coverage within countries. Given the large unmet need for care associated with cataract and refractive error, coupled with the fact that highly cost-effective interventions exist, we propose that effective cataract surgery coverage (eCSC) and effective refra...

Introduction In its recent World Report on Vision , the WHO called for an updated approach to monitor eye health as part of universal health coverage (UHC). This project sought to develop a consensus among eye health experts from all world regions to produce a menu of indicators for countries to monitor eye health within UHC. Methods We reviewed t...

Summary Background Many causes of vision impairment can be prevented or treated. With an ageing global population, the demands for eye health services are increasing. We estimated the prevalence and relative contribution of avoidable causes of blindness and vision impairment globally from 1990 to 2020. We aimed to compare the results with the World...

Purpose To provide an update of cataract as a cause of vision loss in Latin America, and analyze gender inequalities in cataract surgical coverage (CSC) and effective CSC (eCSC) in the region. Design Population-based systematic review with longitudinal comparisons. Methods We searched the LILACS and PUBMED for population-based studies reporting c...

Summary Background To contribute to the WHO initiative, VISION 2020: The Right to Sight, an assessment of global vision impairment in 2020 and temporal change is needed. We aimed to extensively update estimates of global vision loss burden, presenting estimates for 2020, temporal change over three decades between 1990–2020, and forecasts for 2050....

Introduction Universal health coverage (UHC) includes the dimensions of equity in access, quality services that improve health and protection against financial hardship. Cataract continues to be the leading cause of blindness globally, despite cataract surgery being an efficacious intervention. The aim of this scoping review is to map the nature, e...

Significance: Uncorrected refractive error is the leading cause of visual impairment; therefore, reducing its prevalence is important worldwide. For two decades, there has not been a comprehensive assessment of refractive error in Latin America. Purpose: The purpose of this study was to determine the current prevalence of refractive error, presb...

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 t...

Objective To explore sociogeographical inequalities in the availability and distribution of ear, nose and throat specialists (ENTs) in 15 Latin American (LA) countries. Design Ecological. Setting Spanish and Portuguese-speaking countries of LA. The number of registered ENTs in 2017 was obtained from the National ENT Society in each country. Outc...

Retinopathy of prematurity (ROP) is the main cause of blindness and visual impairment in Latin America and prevention, detection and treatment have been a priority in the Region in the last two decades. There is progress in the number of eligible babies screened and treated in at least half of the countries with strong regulations on ROP, but scree...

Purpose: To estimate the prevalence of blindness and visual impairment in older adults living in Guatemala. Methods: Participants ³50 years of age were selected using random cluster sampling and evaluated using the Rapid Assessment of Avoidable Blindness method. Visual acuity was measured, and the lens was examined. If presenting visual acuity w...

Many low- and middle-income countries use national eye-care plans to guide efforts to strengthen eye-care services. The World Health Organization recognizes that evidence is essential to inform these plans. We assessed how evidence was incorporated in a sample of 28 national eye-care plans generated since the Universal eye health: a global action...

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...

Objective To assess the impact of efforts to reduce visual impairment by detecting and treating refractive errors (REs) among schoolchildren in two urban areas of Chile. Methods In 2013, in the communities of Concepción and La Florida, we conducted a multicenter, multistage-sampling, cross-sectional study employing methods used by the Refractive E...

Retinopathy of prematurity (ROP) is a largely avoidable cause of blindness in children worldwide, requiring high-quality neonatal care, early detection and treatment. In middle-income countries throughout Latin America, Eastern Europe and South Asia, there has been a rise in ROP blindness due to a combination of increased survival of preterm infant...

Avoidable blindness is an important global public health concern. This study aimed to assess Trinidad and Tobago's progress towards achieving the Pan American Health Organization, 'Strategic Framework for Vision 2020: The Right to Sight-Caribbean Region,' indicators through comprehensive review of the eyecare system, in order to facilitate health s...

Background Contemporary data for causes of vision impairment and blindness form an important basis of recommendations in public health policies. Refreshment of the Global Vision Database with recently published data sources permitted modelling of cause of vision loss data from 1990 to 2015, further disaggregation by cause, and forecasts to 2020. M...

Background: Contemporary data for causes of vision impairment and blindness form an important basis of recommendations in public health policies. Refreshment of the Global Vision Database with recently published data sources permitted modelling of cause of vision loss data from 1990 to 2015, further disaggregation by cause, and forecasts to 2020. M...

Background: Global and regional prevalence estimates for blindness and vision impairment are important for the development of public health policies. We aimed to provide global estimates, trends, and projections of global blindness and vision impairment. Methods: We did a systematic review and meta-analysis of population-based datasets relevant...

Background No comprehensive study currently exists on the supply of ophthalmologists across Latin America. We explored sociogeographic inequalities in the availability and distribution of ophthalmologists across 14 Latin American countries. Methods The National Ophthalmologic Societies of Argentina, Bolivia, Brazil, Colombia, Costa Rica, Chile, th...

Objective. To consolidate available information from the Latin American and Caribbean (LAC) region on 1) national incidence of retinopathy of prematurity (ROP) and 2) national-level government inputs on ROP (existing national policies, guidelines, programs, and financing for ROP prevention, detection, and treatment, including ROP screening) in 2014...

A prevalence survey for active trachoma in children aged under 10 years and trichiasis in women aged 40 years and older was carried out in four districts in the Sololá region in Guatemala, which is suspected of still having a trachoma problem. Population-based surveys were undertaken in three districts, within 15 randomly selected communities in ea...

To review data on functional low vision (FLV) (low vision-visual acuity (VA) < 6/18 (<20/60) to > perception of light (PL+) in the better eye-that is untreatable and uncorrectable) in adults aged 50 years or older from published population-based surveys from 15 countries in Latin America and the Caribbean. Data from 15 cross-sectional, population-b...

Determine the prevalence of blindness and avoidable visual impairment in Argentina, its causes, the coverage of cataract surgery, and the barriers that hinder access to these services. Cross-sectional population study conducted between May and November 2013 using the standard methodology for rapid assessment of avoidable blindness (RAAB), with a ra...

To conduct a comparative analysis of social inequalities in eye health and eye health care and generate baseline evidence for seven Latin American countries as a benchmarking exercise for monitoring progress toward three goals of the regional Plan of Action for the Prevention of Blindness and Visual Impairment: increasing eye health service coverag...

Objetivo. Determinar la prevalencia de ceguera y deficiencia visual evitable en Argentina, sus causas, la cobertura de cirugía de catarata y las barreras que impiden acceder a esos servicios. Métodos. Estudio poblacional transversal realizado entre mayo y noviembre de 2013 mediante la metodología estándar de evaluación rápida de ceguera evitable. S...

Objective. Determine prevalence of blindness and visual impairment in adults aged ≥ 50 years in Panama, identify their main causes, and characterize eye health services. Methods. Cross-sectional population study using standard Rapid Assessment of Avoidable Blindness methodology. Fifty people aged ≥ 50 years were selected from each of 84 clusters ch...

Determine prevalence of blindness and visual impairment in adults aged > 50 years in Panama, identify their main causes, and characterize eye health services. Cross-sectional population study using standard Rapid Assessment of Avoidable Blindness methodology. Fifty people aged > 50 years were selected from each of 84 clusters chosen through represe...

To examine the prevalence of blindness, visual impairment, and related eye diseases and conditions among adults in El Salvador, and to explore socioeconomic inequalities in their prevalence by education level and occupational status, stratified by sex. Based upon the Rapid Assessment of Avoidable Blindness (RAAB) methodology, this nationwide sample...

OBJETIVO: Estimar la prevalencia de ceguera y deficiencia visual en adultos de Perú y precisar sus causas, evaluar la cobertura y la calidad de los servicios de cirugía de catarata y determinar las barreras que impiden acceder a esos servicios. MÉTODOS: Estudio poblacional transversal con muestreo aleatorio por conglomerado en dos pasos de personas...

OBJETIVO: Determinar la prevalencia de ceguera y deficiencia visual en Honduras, sus causas y la respuesta que los servicios de salud están dando a la creciente demanda. MÉTODOS: Estudio poblacional transversal realizado entre junio y diciembre de 2013 mediante la metodología estándar de evaluación rápida de ceguera evitable. Se realizó un muestreo...

To determine the prevalence of blindness and visual impairment in Honduras, its causes and the response by the health services to growing demand. A cross-sectional population study was conducted between June and December 2013 using the standard methodology of the Rapid Assessment of Avoidable Blindness. A random sample survey was done in 63 cluster...

To estimate the prevalence of blindness and visual impairment among adults in Peru and to determine their causes, to evaluate the coverage and quality of the cataract surgical services and to investigate the barriers that inhibit access to these services. A cross-sectional population study with two-stage random cluster sampling of individuals of ≥...

Purpose: Although international policies promote programs for correction of refractive errors in school children, recent studies report low compliance with respect to spectacle wear. Our aim was to assess spectacle-wear compliance and identify associated visual factors among children participating in Chile's school spectacle provision program. Me...

OBJETIVO: Describir la justificación y metodología usadas en la Evaluación Rápida de Ceguera Evitable empleada para efectuar encuestas a nivel nacional entre 2011 y 2013 en Argentina, El Salvador, Honduras, Panamá, Perú y Uruguay. MÉTODOS: La encuesta se dirige a personas de 50 años o más, lo que reduce al mínimo los requisitos de tamaño de la mues...

To investigate and describe the prevalence and causes of blindness and moderate and severe visual impairment in older adults living in Uruguay. All individuals aged ≥ 50 years old living in randomly selected clusters were eligible to participate. In each census enumeration unit selected, 50 residents aged 50 years and older were chosen to participa...

Describe the rationale and methodology of the Rapid Assessment of Avoidable Blindness applied in surveys at the national level in 2011-2013 in Argentina, El Salvador, Honduras, Panama, Peru, and Uruguay. The survey includes individuals aged 50 years and older, minimizing required sample sizes, which vary from 2 000 to 5 000 people. It uses straight...

To provide an update of cataract data and cataract surgical barriers in Latin America. Design: review; longitudinal study METHODS: Cataract surgical rates and other related indicators that have been reported to the VISION 2020 Latin America program since 2005 were reviewed. PubMed was searched for publications on regional epidemiological studies re...

Objective: To present regional estimates of the magnitude and temporal trends in the prevalence and causes of blindness and moderate/severe visual impairment (MSVI) in Latin America and the Caribbean (LAC). Methods A systematic review of cross-sectional population-representative data from published literature and unpublished studies was accessed a...

Purpose: To report the prevalence and causes of blindness in people aged 50 years and older in Paraguay, and to compare these with the previous national survey in 1999, focusing on planning of future eye care activities. Methods: A rapid assessment of avoidable blindness (RAAB) was conducted in 2011. A total of 60 clusters of 50 residents aged 5...

Since the inception of (the Global Elimination of Blinding Trachoma) GET 2020 in 1997 and the implementation of the SAFE strategy a year later, much progress has been made toward lowering the prevalence of trachoma worldwide with elimination of the disease in some countries. However, high recurrence of trichiasis after surgery, difficulty in contro...

Objective To estimate and compare the incidence of operable cataract and the desired cataract surgery rates required to eliminate cataract-related visual impairment in several Latin American settings. Methods We obtained raw data on age-specific cataract prevalence from standardized population-based surveys. We used the data in a previously describ...

Knowledge about a number of public health problems is gathered mainly from mortality statistics, which traditionally have provided the highest–quality and highest–coverage information about health available in many countries. The quality of mortality data in the Region of the Americas has improved in recent years, as national vital statistics syst...

We review what is known in each country of the Latin American region with regards to blindness and visual impairment and make some comparisons to Hispanic populations in the United States. Prevalence of blindness varied from 1.1% in Argentina to 4.1% in Guatemala in people 50 years of age and older, with the major cause being cataract. Diabetic ret...

  To determine if gender inequities exist in Latin America in regard to cataract surgery.   Meta-analysis.   Total of 38,992 subjects participating in epidemiological surveys; summary measures were used (not patient-level data).   A literature search and knowledge of rapid assessment of cataract surgical services/rapid assessment of avoidable blind...

For decades, onchocerciasis (or river blindness) was one of the most common infectious causes of blindness in the world. Primarily an infection of Africa, with limited distribution in the new world, disease due to the nematode Onchocerca volvulus is rapidly diminishing as a result of large public health campaigns targeting at risk populations in Af...

In Latin America and the Caribbean, around 195 million people live in poverty, a situation that increases the burden of some infectious diseases. Neglected diseases, in particular, are often restricted to poor, marginalized sections of the population. Tools exist to combat these diseases, making it imperative to work towards their elimination. In 2...

To collect cataract surgery rates data in 19 Latin American countries over a 4-year period as data published to date have been limited. Cataract surgery rates were obtained from National Society of Ophthalmology, National VISION 2020/Prevention of Blindness Committee and Ministry of Health representatives for each country for 2005 to 2008. Economic...

VISIÓN 2020: El Derecho a la Visión, es una iniciativa conjunta de la Organización Mundial de la Salud (OMS) y la Agencia Internacional para la Prevención de la Ceguera IAPB - por sus siglas en inglés), con una coalición de entidades internacionales, instituciones de atención oftalmológica, organizaciones no gubernamentales y corporaciones. VISIÓN...

To review recent data on blindness and low vision due to cataract in Latin America. Presentation of findings from population-based prevalence surveys conducted between 1999 and 2006 in nine Latin American countries covering 30,544 people aged 50 years and older. Prevalence of cataract blindness in people 50 years and older ranged from 0.5% in Bueno...

To review recent data on prevalence and causes of blindness and visual impairment in Latin America. Data from recent population-based prevalence surveys in nine countries in Latin America, covering 30,544 people aged 50 years and older, are presented. The prevalence of bilateral blindness (VA <3/60 in the better eye with available correction) range...

To assess prevalence of visual impairment resulting from cataract and cataract surgical services in 4 departments (provinces) of Guatemala to facilitate further health care planning. Cross-sectional study. Ninety-eight enumeration areas were selected by systematic sampling in 4 departments in southwest Guatemala, with a combined population of 1,339...

To present results of a rapid assessment on visual impairment due to cataract and on cataract surgical services in the Northwestern districts of Buenos Aires, Argentina. These results will enable health managers to plan effective interventions in this area in line with VISION 2020. One hundred fifteen clusters of 40 persons of 50 years and older in...

OBJETIVE: To determine the prevalence of blindness and of cataract blindness in persons 50 years of age or older in Piura and Tumbes, which are two departments in northern Peru, and to describe the coverage and quality of cataract surgery services in that area, and the barriers that prevent access to those services. METHODS: Systematic sampling of...

To determine the prevalence of blindness and of cataract blindness in persons 50 years of age or older in Piura and Tumbes, which are two departments in northern Peru, and to describe the coverage and quality of cataract surgery services in that area, and the barriers that prevent access to those services. Systematic sampling of persons 50 years ol...

Objective. To determine the prevalence of blindness and of cataract blindness in persons 50 years of age or older in Piura and Tumbes, which are two departments in northern Peru, and to describe the coverage and quality of cataract surgery services in that area, and the barriers that prevent access to those services. Methods. Systematic sampling of...