These cutaneous manifestations affect mobility and social acceptability. Ocular manifestations By slit lamp biomicroscopy, the microfilariae can be seen within the cornea, migrating in the anterior chamber and the vitreous humor freely. Although live microfilariae cause minimum reaction, dead microfilariae are associated with severe inflammatory response. Onchocerciasis-related blindness results from decades of infection and reinfection. Keratitis is one of the most devastating consequences of onchocerciasis.
Larval death induces an inflammation that results in corneal opacification and neovascularization.
Dead worms are surrounded by inflammatory infiltrates in the superficial stroma. Lymphocytes and eosinophils migrate to the peripheral cornea where the infection is more dense. A sclerosing keratitis follows, which may involve the visual axis over time. Corneal neovascularization and opacification with interstitial keratitis lead to corneal blindness. The development of keratitis is dependent upon the previous immunization and the presence of sensitized T lymphocytes.