Valor do corante vital Rosa Bengala como auxiliar no diagnóstico de xerose conjuntival em provas de triagem

Abstract

Demonstrou-se o valor do corante vital Rosa Bengala no diagnóstico da xerose conjuntival e determinou-se a prevalência de lesões oculares devidas à hipovitaminose A. Estudou-se uma amostra representativa (501 crianças) da população de 3 a 6 anos do Município de Cotia, SP (Brasil). Realizaram-se exames com e sem o uso de Rosa Bengala nas 501 crianças. As positivas para qualquer das técnicas foram submetidas a prova terapêutica (200.000 UI de vitamina A oral). Examinaram-se as córneas com fluoresceína, quando necessário. Realizou-se dosagem de vitamina A pelo método de Carr-Price. Não se observaram outras lesões, além de xerose conjuntival. Verificou-se que as prevalências de resultados positivos foram de 10,0% sem Rosa Bengala e 18,2% com o corante. As provas terapêuticas revelaram sensibilidade e especificidade baixas para o exame sem Rosa Bengala (18,5% e 14,3%, respectivamente) e altas para o exame com Rosa Bengala (81,5% e 89,0%, respectivamente), o que o indica como método diagnóstico auxiliar para provas de triagem.The present paper was designed to demonstrate the value of Rose Bengal in the diagnosis of conjunctival xerosis and at the same time determine the prevalence of ocular lesions due to vitamin A deficiency. A representative sample (501 children) between 3 and 6 years of age drawn from the population of the city of Cotia, SP, Brazil, was studied. Ocular examinations with and without the aid of Rose Bengal were performed on the 501 children. Those that presented positive results were submitted to a therapeutic test (200.000 IU of vitamin A orally). Whenever necessary corneae were examined with fluorescein. Vitamin A blood levels were determined by the Carr-Price method. No lesions beyond conjunctival xerosis were found. Examinations performed without the aid of Rose Bengal rendered 10.0% positive results whereas Rose Bengal tests rendered 18.2% positive results. Therapeutic tests showed low sensitivity and low specificity for the examinations without Rose Bengal (18.5% and 14.3%, respectively) and high sensitivity and specificity for examinations performed with Rose Bengal (81.5% and 89.0%, respectively). Based on our results the ocular examinations without the aid of Rose Bengal are not recommended for screening tests, whereas those performed with Rose Bengal are.