A refractive error is the second major cause of visual impairment. Despite that it can be corrected simply by a pair of spectacles, millions remain blind or visually impaired due to uncorrected refractive error. Uncorrected refractive error remains largely unaddressed – this is contributed to by a complicated web of barriers. Poor awareness amongst those requiring care, low priority for eye care in life choices compounded by poor access to care and affordable spectacles reduces the number of those seeking care. This Site news explores the Prevalence and Magnitude of Refractive Error
, Impact of Uncorrected Refractive Error
, Refractive Errors and Low Vision
, Risk Factors
, and Barriers
. This issue also covers Refractive Error and Services
, and Screening Programs
. In this issue, Featured Organization
is The International Society of Refractive Surgery (ISRS), a partner of the American Academy of Ophthalmology is the leading worldwide organization for refractive surgeons. The Featured Personality
is a Dutch ophthalmologist, Hermann Snellen who introduced the Snellen chart to study visual acuity (1862). He took over directorship of the Netherlands Hospital for Eye Patients.
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Uncorrected refractive error is the main cause of low vision and the second major cause of blindness. An estimated 153 million people are visually impaired due to uncorrected refractive error of whom, 8 million are blind. Refractive errors are disorders, not diseases. This disorder is easily correctible. While contact lenses and refractive surgery are among the effective solutions for refractive error, spectacles remain the most affordable solution that can be effectively dispensed to the large underserved populations.
Though refractive error demands attention as a priority eye condition by Vision 2020; service providers themselves do not see it as a vital service – hospitals place more attention on developing other eye care services. Though many hospitals perform outreach camps – these almost exclusively focus on cataract screening. People tend to cope with refractive error.
People with refractive error tend to cope with the error and do not proactively seek care.This is also contributed to by poor access to screening facilities and spectacle dispensing services. This has resulted in poor coverage– less than 10% of those who need refractive correction have been covered. This issue of SiteNews explores the problem of refractive error – the challenges and solutions.
- REFRACTIVE ERROR BLINDNESS
This review presents a summary of the current and likely future issues related to blindness due to refractive error.
- REFRACTIVE ERRORS: MAGNITUDE OF THE NEED
- MORE RESEARCH NEEDED TO ASSESS THE MAGNITUDE OF REFRACTIVE ERRORS WORLD-WIDE
Elimination of visual impairment (less than 6/18) and blindness due to refractive errors or other causes of low vision. This aim goes beyond the elimination of blindness and also includes the provision ofservices for individuals with low vision. This article fpointedout Clearly, there is a major need to assessvision and to improve it by whatever means are needed. It is remarkable that such a large proportion of vision loss can be rectified with the simple provision of an appropriate pair of spectacles.
- GLOBAL MAGNITUDE OF VISUAL IMPAIRMENT CAUSED BY UNCORRECTED REFRACTIVE ERRORS IN 2004
Refractive error as a cause of visual impairment has been overlooked in previousestimates that were based on best-corrected vision. Uncorrected refractive errors can hamper performance at school, reduce employability and productivity, and generally impair quality of life. Yet the correction of refractive errors with appropriate spectacles is among the most cost-effective interventions in eye health care. The results presented in this paper help to unearth a formerly hidden problem of public health dimensions and promote policy development and implementation, programmatic decision-making and corrective interventions, as well as stimulate research.
- PREVALENCE OF UNDETECTED REFRACTIVE ERRORS AMONG SCHOOL CHILDREN
In Pakistan 11.4% of the blindness is due to uncorrected refractive errors. This study was carriedout in two schools of Lahore to find the prevalence of refractive errors among high school children.It was an institution – based, cross sectional study involving the use of structured questionnaireand visual examination of the students.
- PREVALENCE OF REFRACTIVE ERRORS IN PRIMARY SCHOOL CHILDREN [7-15 YEARS] OF QAZVIN CITY
Main aim of this study was to assess the prevalence of refractive error and related visual impairment in school children between 7-15 years in the city of Qazvin NortheasternIran. Cross-sectional study performed in schools of Qazvin city conducted from October2002 to September 2008 for 5913 school children.
- THE PREVALENCE OF REFRACTIVE ERROR IN THREE COM¬MUNITIES OF CAPE TOWN, SOUTH AFRICA
This article focuses on the prevalence distribution and demographic association of refractive errors three com¬munities of Cape Town, South Africa
- REFRACTIVE ERROR IN SCHOOL CHILDREN IN AGONASWEDRU, GHANA
Uncorrected refractive errors remains a public health problem among different population groups. Among schoolchildren, uncorrected refractive er¬rors have a considerable impact on learning and academic achievement especially in underserved and under-resourced communities. A school based cross-sectional study was carried out to estimate the prevalence and distribution of refractive error among schoolchildren in the AgonaSwedru municipality of Central Region of Ghana.
- WORLDWIDE DISTRIBUTION OF VISUAL REFRACTIVE ERRORS AND WHAT TO EXPECT AT A PARTICULAR LOCATION
- PREVALENCE OF UNCORRECTED REFRACTIVE ERROR AND OTHER EYE PROBLEMS AMONG URBAN AND RURAL SCHOOL CHILDREN
To compare the magnitude and determinants of uncorrected refractive error, such as age, sex, family history of refractive error and use of spectacles among school children 6-15 years old in urban and rural Maharashtra, India.
- THE IMPACT OF UNCORRECTED REFRACTIVE ERROR ON GLOBAL HEALTH
Uncorrected refractive error is a major cause of blindness and the leading cause of visualimpairment in the world. This work reviews the current literature on the prevalence ofuncorrected refractive error, eyeglass utilization, the reported solutions to uncorrectedandundercorrected refractive error and visual-related quality of life measurements.
- UNCORRECTED REFRACTIVE ERROR: THE MAJOR AND MOST EASILY AVOIDABLE CAUSE OF VISION LOSS
World HealthOrganization (WHO) and the InternationalAgency for the Prevention of Blindness(IAPB), both separately and in their jointinitiative, VISION 2020: The Right to Sight,have worked very hard to put uncorrectedrefractive error on the blindness preventionagenda and to develop strategies for theelimination of this most simple avoidablecause of vision loss.
- POTENTIAL LOST PRODUCTIVITY RESULTING FROM THE GLOBAL BURDEN OF UNCORRECTED REFRACTIVE ERROR
Uncorrected refractive error (URE) for distance vision, including undercorrected refractive error in more economically developed countries, has recently been highlighted as the main cause of low vision globally and the second leading cause of blindness after cataract. An estimated 153 million people had visual impairment (VI) from URE in 2004, and 8 million of them were blind. The magnitude of this correctable burden of VI has been overlooked because epidemiological studies have tended to focus on “best corrected” sight rather than presenting visual acuity (VA). Present estimates of the magnitude of URE include myopia (short-sightedness) and hypermetropia (far-sightedness), but they do not include presbyopia (an age-related impairment of near vision), for which there are few data on prevalence or visual function.
- MILLIONS ARE FUNCTIONALLY BLIND FOR THE LACK OF ACCESS TO SPECTACLES
Refractive errors (myopia, hypermetropia, astigmatism, presbyopia) result in an unfocussed image falling on the retina. Uncorrected refractive errors, which affect persons of all ages and ethnic groups, are the main cause of vision impairment. They may result in lost education and employment opportunities, lower productivity and impaired quality of life.
- ELIMINATION OF AVOIDABLE VISUAL DISABILITY DUE TO REFRACTIVE ERROR
- REFRACTIVE ERRORS AND LOW VISION
The Role of Optometry in VISION 2020:
- Strategies for Correcting Uncorrected Refractive Errors: The Challenge of providing
- Spectacles in the Developing World
- Vision Testing for Refractive Errors in Schools
- Case Finding for Refractive Errors: Assessment of Refractive Error and Visual Impairment in Children
- Case Finding in the Clinic: Refractive Errors Guidelines for Setting Up a Child Based Low Vision Programme for Children
- Optical Services for Visually Impaired Children.
The impact and importance of uncorrected refractiveerror has now been recognised by VISION 2020. WHOestablished a Refractive Error Working Group (REWG)as part of global VISION 2020 activities, in recognitionof this important facet of international eyecare. TheREWG is now developing international strategic plansand policies to eliminate uncorrected refractive error.
- RISK FACTORS FOR REFRACTIVE ERRORS IN PRIMARY SCHOOLCHILDREN (6-12 YEARS OLD) IN NAKHON PATHOM PROVINCE
The present study was a population-based cross-sectional descriptive study of children between 6-12 years old primary school children in NakhonPathom, chosen from three schools between October 2008 and September 2009. The ethical approval involving human subjects was granted by Mettapracharak Hospital, Nakhon Pathom research ethics committee to carry out the present study.
- ENVIRONMENTAL RISK FACTORS FOR REFRACTIVE ERROR AMONG EGYPTIAN SCHOOL CHILDREN
This study evaluated the preventable environmental risk factors of refractive error (RE) among 1292 Egyptian schoolchildren aged 7-15 years, chosen from 12 schools using multistage random sampling. A questionnaire was completed, covering personal, medical, social and environmental data. Statistical analysis revealed that living in an area with many sources of environmental pollution, age, sex, family history of RE, socioeconomic status, ocular problems, school level and amount of near work (hours/day) were significantly associated with RE. Logistic regression, after adjustment for sex, found that school level, near-work, socioeconomic status, and family history were associated with RE.
- POPULATION-BASED CROSS-SECTIONAL STUDY OF BARRIERS TO UTILISATION OF REFRACTION SERVICES IN SOUTH INDIA: RAPID ASSESSMENT OF REFRACTIVE ERRORS (RARE) STUDY
Addressing the huge need forcorrection of uncorrected refractive error is one of the priorities of the global initiative VISION 2020: The Right to Sight. Uncorrected presbyopia is increasingly recognised as a major problem across the world. Recent estimates by Holden et al have revealed that nearly 410 million people havenear visual impairment due to uncorrected presbyopia. Several studies have underscored the impact of uncorrected presbyopia onthe quality of life in individuals in rural settings. Recent studies make it clear that the impact of uncorrected presbyopia is notlimited to literate populations living in urban areas. The barriers that were ‘relatively easy to change’ were reported by those with uncorrected refractive errors in contrast to ‘difficult to change’ barriers reported by those with uncorrected presbyopia. Together, the data on prevalence and an understanding of the barriers for the uptake of services are critical to the planning of refractive error services.
- POOR VISION, REFRACTIVE ERRORS AND BARRIERS TO TREATMENT AMONG COMMERCIAL VEHICLE DRIVERS IN THE CAPE COAST MUNICIPALITY
The purpose of the present study was to determine the prevalence of visual impairment and refractive error among commercial drivers in the Cape Coast municipality, study the barriers to the use of eye care services and spectacle correction and explore the relationship between visual function and the occurrence of road traffic accidents.
- BARRIERS TO SPECTACLE USE IN TANZANIAN SECONDARY SCHOOL STUDENTS
Screening school students for refractive errors is a component of many primary eye care programs. In 2004 a trial of two approaches of spectacle-delivery to Tanzanian secondary school students found that only one third of students were using their spectacles at three months. Barriers to spectacle use were investigated using questionnaires and focus group discussions.
- DELIVERING REFRACTIVE ERROR SERVICES:PRIMARY EYE CARE CENTRES AND OUTREACH
The delivery of comprehensive refractive error services at the primary level requires the following:
• a trained person to refract and provide counselling about refractive error as part of a general eye examination and service
• equipment for vision testing, refraction, and spectacle dispensing
• Spectacles which are acceptable and affordable to the patient.
- MAKING REFRACTIVE ERROR SERVICES SUSTAINABLE: THE INTERNATIONAL EYE FOUNDATION MODEL
The International Eye Foundation (IEF) believes that the most effective strategy for making spectacles affordable and accessible is to integrate refractive error services into ophthalmic services and to run the refractive error service as a business – thereby making it sustainable. An optical service should be able to deal with high volumes of patients and generate enough revenue – not just to cover its own costs, but also to contribute to ophthalmic clinical services.
- ESTABLISHING SUSTAINABLE REFRACTIVE ERROR SERVICES IN THE DEVELOPING WORLD
Uncorrected refractive error is the most treatable cause of visual impairment – most cases can beeasily and cost-effectively managed with a basic eye examination and spectacles.
- HOW TO BROADEN THE AVAILABILITY OF EYEGLASSES WORLDWIDE?COUNCIL ON FOREIGN RELATIONS GLOBAL HEALTH ROUND TABLE
The World Health Organization estimates that 333 million people are blind or visually impaired, and that 153 million, or nearly half of the global burden of blindness and visionimpairment, is due to uncorrected refractive error. The WHO measurement of refractiveerror encompasses myopia (nearsightedness), hyperopia (farsightedness), and astigmatism. Not included in this estimate are 150 million people with presbyopia, age-related farsightedness, which puts the total global burden of visual impairment due to lack ofeyeglasses at 303 million. An estimated 90% of people with uncorrected refractive error live in low and middle income countries.
- SEEING THE WORLD THROUGH NEW LENSES: PROVIDING REFRACTIVE ERROR
A2Z Child Blindness Program: Tackling Avoidable Blindness through Partnerships nearly 17 million children with low vision or impaired sight lack the eyeglasses, visual aids, or services they need to help them function. As a component of A2Z: The USAID Micronutrient and Child Blindness Project, the A2Z Child Blindness Program uses competitive grants to reduce child blindness and improve eye health through support to NGOs that deliver services to populations in need.
- REFRACTIVE ERRORS SERVICES POLICY
The Refractive Errors Services Policy is based on inputs from Sightsavers personnel throughout the organisation, partner organisations, other external agencies and consumers. It builds on Sightsavers Strategic Framework 2009 - 2013 and complements our change themes; health, education, social inclusion, and community participation and development. This policy is fundamentally about our values and in accordance with our strategic direction, key priority areas and capacity. It provides concrete direction as how we, as an organisation, can support the development of services for refractive error based on best practice and defined quality standards.
- CHALLENGES, ATTITUDES AND PRACTICES OF THE SPECTACLE WEARERS IN A RESOURCE-LIMITED ECONOMY
To evaluate challenges, attitudes and practices among spectacles wearers to effect positive change when necessary, and determine positive change in a resource-limited economy.
- EFFECTIVENESS OF USING TEACHERS TO SCREEN EYES OF SCHOOL-GOING CHILDREN IN SATNA DISTRICT OF MADHYA PRADESH, INDIA
To assess the effectiveness of teachers in a vision screening program for children in classes 5th to 12th attending school in two blocks of a district of north central India.
- ADDRESSING REFRACTIVE ERROR VISUAL IMPAIRMENT: VOLUNTEER ORGANISATIONS ALIGNMENT WITH VISION 2020 AND PUBLIC HEALTH PRINCIPLES
Eye care professionals have been making short visits to developing countries for decades in an effort to reduce visual impairment caused by refractive error. A 2006 survey revealed that volunteer organisations were not working within the Vision 2020 framework. Recommendations were made for volunteer organisations that would better align their work with accepted Vision 2020 and public health principles. This article pointed out some recommendations as well as creating a better alignment with public health principles in general will increase the likelihood that their programs will be effective in decreasing visual impairment due to refractive error in the developing world.
- REFRACTIVE ERROR IN SCHOOL CHILDREN: A REVIEW FROM PUNJAB
This study was done on students aged 5 yrs. to 15 yrs. from – randomly selected urban as well as rural schools in and around Ludhiana city, Punjab. Formal permission was taken from the principals of these schools. The list of all the students was taken from the attendance registers along with their age, address, telephone number, parents occupation, and whether they were immigrants or not. All students age 5-15 yrs (class 1-10) in these schools were screened. A detailed ocular history was taken about present and past ocular problems along with history of use of spectacles.
- SCREENING FOR VISUAL IMPAIRMENT: OUTCOME AMONG SCHOOL CHILDREN IN A RURAL AREA OF DELHI
This study focuses on the effectiveness of school eye screening in correcting refractive errors and the objectives of the study are 1. To study the magnitude of visual impairment among school children. 2. To assess the compliance of students for refraction testing, procurement and use of spectacles.
- TRAINING TO MEET THE NEED FOR REFRACTIVE ERROR SERVICES
This article shows how two countries, The Gambia and Pakistan, approached the training and integration of refraction personnel in their respective eye care programmes.
- PREVALENCE OF UNCORRECTED REFRACTIVE ERROR AND OTHER EYE PROBLEMS AMONG URBAN AND RURAL SCHOOL CHILDREN
The prevalence of uncorrected refractive error, especially myopia, was higher in urban children. Causes of higher prevalence and barriers to refractive error correction services should be identified and addressed. Eye screening of school children is recommended. However, the approach used may be different for urban and rural school children.
- SCHOOL EYE SCREENING AND THE NATIONAL PROGRAMFOR CONTROL OF BLINDNESS
Childhood blindness and visual impairment are as important and perhaps more devastating and disabling than adult onset blindness, because of the long span of life still remaining to be lived. Refractive errors and more particularly myopia, place a substantial burden on the individual and society. School-age children constitute a particularly vulnerable group where uncorrected refractive errors may have a dramatic impact on learning capability and educational potential. This article provides an overview of school eye screening from the perspective of National Program for Control of Blindness (NPCB), Government of India; and challenges, future directions and thrust area envisaged under the program for amelioration of childhood blindness.
- REDUCED VISION AND REFRACTIVE ERRORS, RESULTS FROM A SCHOOL VISION SCREENING PROGRAM IN KANCHANPUR DISTRICT OF FAR WESTERN NEPAL
The aim of this study was to elucidate the incidence of reduced vision and refractive errors among school children from Kanchanpur district of Far Western Nepal according to their types and relationship with age and gender effective screening of refractive errors could help reduce the proportion of reduced vision among school children. It Conclude with effective screening of refractive errors could help reduce the proportion of reduced vision among school children.
- SNELLEN CHART MAY BE PREFERABLE OVER EARLY TREATMENT DIABETIC RETINOPATHY STUDY CHARTS FOR RAPID VISUAL ACUITY ASSESSMENT
Visual acuity (VA) measurement with early treatment diabetic retinopathy study (ETDRS) charts is considered as the universal standard and is used in most of the clinical trials. The ETDRS charts have numerous advantageous over the Snellen chart. However, over clinical impressions suggest that reading an ETDRS chart requires more time as compared to the Snellen chart.a
- PROSPECTIVE EVALUATION OF VISUAL ACUITY ASSESSMENT: A COMPARISON OF SNELLEN VERSUS ETDRS CHARTS IN CLINICAL PRACTICE (AN AOS THESIS)
The purpose of this study was twofold: first, to prospectively compare visual acuity (VA) scores obtained with Snellen charts versus Early Treatment Diabetic Retinopathy Study (ETDRS) charts in a “real world” retinal practice, and second, to see if there was a difference in visual acuity measurements obtained with ETDRS charts starting at 4 or 2 meters.
- COMPARING THE COST-EFFECTIVENESS OF SCHOOL EYE SCREENING VERSUS A PRIMARY EYE CARE MODEL TO PROVIDE REFRACTIVE ERROR SERVICES FOR CHILDREN IN INDIA
To compare the cost-effectiveness of school eye screening(SES) for refractive errors with a primary eye care (PEC) model thatprovides comprehensive eye care, including refractive services, to children of school age.
- ISRS – INTERNATIONAL SOCIETY OF REFRACTIVE SURGERY
The International Society of Refractive Surgery (ISRS), a partner of the American Academy of Ophthalmology is the leading worldwide organization for refractive surgeons. ISRS keeps you up-to-date on the latest clinical and research developments in refractive, cornea, cataract and lens-based surgery.
Members are connected to the world’s leading refractive surgeons from over 80 countries through its innovative educational programs, clinical journal, monthly newsletter and meetings around the world.
A Global Organization
ISRS is committed to being a truly global organization, representing the interests and serving the needs of refractive surgeons worldwide. One way ISRS ensures its universal nature is through the International Council, comprised of refractive ophthalmologists from around the world.
- HERMANN SNELLEN
Herman Snellen (February 19, 1834 to January 18, 1908) was a Dutch ophthalmologist who introduced the Snellen chart to study visual acuity (1862). He took over directorship of the Netherlands Hospital for Eye Patients after Dr. Franciscus Donders.
Snellen was born in Zeist, Netherlands. He studied medicine at Utrecht University under Franciscus Donders, Gerardus Johannes Mulder and Jacobus Schroeder van der Kolk, earning his medical degree in 1858. He specialized in ophthalmology, working as an assistant physician at the Netherlands Hospital for Eye Patients (Nederlandsch Gasthuisvoor Ooglijders) after completing his degree. He was named to succeed Donders as the institute's director in 1884, a position he served in until 1903. In 1877 he was appointed as a professor of ophthalmology at Utrecht University. He did research on astigmatism, glaucoma and other eye diseases, as well as research on correction of visual acuity using eyeglasses and ophthalmological surgery.
While other versions had been developed before him by Eduard Jäger von Jaxtthal and others, Snellen developed his eponymous eye chart in 1862 to measure visual acuity, which rapidly become a global standard. The most significant innovation was his use of what he called optotypes, specially designed characters generated on a 5x5 grid, rather than using standard fonts. They provide a physical standard measure that could be used when printing the chart. Standard vision was measured as the ability to correctly read a line of optotype characters when they subtended 5 minutes of arc and were separated by 1 minute of arc.
Since its inception, more copies of the SnellenChart have been sold in the United States than any other poster. It has remained a ubiquitous standard in medical offices into the 21st century.
Snellen died in Utrecht.
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