Prueba de tamizaje simplificada para identificar a personas con visión disminuida en países en desarrollo / A simplified screening test for identifying people with low vision in developing countries

Se han creado pruebas sencillas pero útiles para el tamizaje de personas con visión disminuida en países en desarrollo. Estas pruebas, que miden la visión de lejos y de cerca y que se basan en el uso de una figura en E, fueron evaluadas y respaldadas mediante ensayos en que participaron personas de 4 a 90 años de edad, y se han puesto a prueba en los servicios de salud, educación y rehabilitación de 32 países en desarrollo. Se han calculado su sensibilidad y especificidad como instrumentos para la detección de la visión disminuída: en la prueba de visión a distancia, la sensibilidad es de 85 por ciento y la especificidad, de 96 por ciento; en la prueba de visión cercana, la sensibilidad es de 100 por ciento y la especificidad, de 84 por ciento. Se ha demostrado que el contenido y el formato de las pruebas son adecuados para países en desarrollo y se ha comprobado la utilidad de las mismas para el tamizaje de la visión disminuida

Simple but effective tests have been produced for screening subjects with low vision in developing countries. These tests of distance and near vision, based on the E test, were evaluated and validated in trials with people aged 4­90 years, and have been field tested in the health, education and rehabilitation services in 32 developing countries. Their sensitivity and specificity as screening tools for low vision have been calculated: sensitivity of 85% and specificity of 96% for the distance vision test, and sensitivity of 100% and specificity of 84% for the near vision test. The content and format of the tests have been demonstrated to be appropriate for developing countries, and their effectiveness for screening for low vision has been confirmed.

The epidemiology of trachoma in southern Malawi

A population-based prevalence survey of ocular disease was conducted in the Lower Shire Valley of Malawi in 1983. A total of 5;436 children less than 6 years of age and 1;664 persons greater than or equal to 6 years were examined. The prevalence of inflammatory trachoma peaked in the 1-2-year-old age group at 48.7 percent and declined rapidly with age to less than 5 percent by age 15. The prevalence of cicatricial trachoma was low in young children and climbed gradually with age to greater than 40 percent among those greater than or equal to 50 years. Risk factors for infLammatory disease in young children included low socioeconomic status of the family; long walking distance to the household's primary source of water; absence of a latrine in the family compound; and presence of trachoma among siblings. Indices of crowding practices were not associated with inflammatory disease. An apparent inverse association of facewashing and inflammatory trachoma in children did not hold up when adjusted for other risk factors

Trachoma grading: observer trials conducted in southern Malawi

A variety of grading schemes have been proposed for the clinical classification of inflammatory trachoma. During a population based study of ocular disease conducted in southern Malawi we tested a simplified version of the current WHO grading scheme. Intraobserver agreement statistics were less than satisfactory for three of four graders. Interobserver agreement when compared against either a well experienced standard ophthalmologist or a consensus grade improved over time for two of the three graders. However; initial agreement for all three graders was only fair to moderate. Previous studies of trachoma grading schemes support these unsatisfactory results. A new system of classification is needed that is both accurate and reliable in a field setting