Eye disease related to onchocerciasis: A clinical study in the Aratha-ú, Yanomami Tribe, Roraima State, Brazil

The prevalence of ocular lesions due to onchocerciasis was evaluated among residents of the Yanomami Tribe, in the northern Amazon, Brazil, an endemic area for onchocerciasis. 83 natives were submitted to an ocular examination including an external examination, biomicroscopy, intraocular pressure measurement, and a fundus examination. Clinical, parasitological and serological tests were carried out simultaneously. The population demonstrated a high prevalence of eosinophilia, skin microfilaria (55%) and onchocercal subcutaneous nodules (35%). A high prevalence of probable onchocerciasis related eye lesions was detected. Punctate keratitis (41%) and microfilaria in the anterior chamber (39%) were found as well as other probable onchocercotic lesions—chorioretinitis (7.2%) and anterior uveitis (6.0%). Other anterior eye lesions (corneal leucomas, conjunctival injection, lid nodules) occurred in 51% of the individuals. The anterior eye lesions were more prevalent than the posterior lesions. We did not find an association of glaucoma with onchocerciasis. The prevalence of these suggestive ocular lesions strongly correlates with the cutaneous nodules and eosinophilia, suggesting that skin nodules may be an indication for an eye examination. The present study provides evidence that significant infection and eye disease due to onchocerciasis persists in certain regions of Northern South America.