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

Summary 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.