Profile of eye lesions and vision loss: a cross-sectional study in Lusambo, a forest-savanna area hyperendemic for onchocerciasis in the Democratic Republic of Congo

OBJECTIVE To determine baseline data regarding eye lesions and vision loss in five villages of Lusambo, an onchocerciasis-hyperendemic forest-savanna area in the Democratic Republic of Congo (DRC), in preparation of mass ivermectin distribution. METHODS Five villages were selected by simple randomization. Through a cross-sectional design, 750 subjects were examined ophthalmologically. The eye examination included acuity visual measurement, slit-lamp examination, ophthalmoscopy, intraocular pressure measurement, and visual field assessment by the Wu-Jones test. RESULTS There was a high prevalence of onchocerciasis-related eye lesions compared with non-onchocercal lesions. Chorioretinitis (20%) was the most frequent disease, others were punctate keratitis and microfilariae in the anterior chamber in equal frequency (13.8%), white intraretinal deposits (10.4%) and iridocyclitis (8%). Vision loss was discovered in 8.5% of the subjects, of whom 0.5% had bilateral blindness, 2.2% had monocular blindness and 5.7% had visual impairment. Vision loss was mostly caused by onchocerciasis-related diseases, especially those affecting the anterior segment of the eye. CONCLUSION Features of ocular onchocerciasis usually described in forest and savanna areas were both found in this forest-savanna zone of the DRC.