Trends in prevalence rates of onchocercal ocular lesions
were examined over the period 1980 to 1990 using data from two
cross-sectional surveys. There was evidence for increasing
prevalence of anterior chamber microfilariae, iridocyclitis,
optic atrophy, and chorioretinopathy. Large increases in
prevalence, in particular, were seen for posterior segment
lesions: optic atrophy increased from 2.7% to 6.4% and
chorioretinopathy from 8.8% to 35.6%. Greatest increases in
these lesions were seen in the Chachi which was attributed to
the large increases in prevalence of microfilariae in the
anterior chamber particularly in those aged 30 years or
greater. The study findings suggest that ocular onchocerciasis
is evolving in parallel with the well documented
parasitological changes.
