New observations on ocular onchocerciasis; related pathological methods and the pathogenesis of the various eye lesions.

The records of 2000 blind or partially blind persons in the onchocerciasis areas of West Africa provided the background information for this report.The author has grouped his material in three sections. The first of these deals with diagnostic methods, and contains the results of skin and conjunctival biopsies, as well as a description of onchocercomas and an estimate of the life-span of Onchocerca adults.Next, the pathogenesis of ocular lesions is discussed in the light of evidence obtained from a series of animal experiments designed to test two theories-namely, the existence of an allergic state and damage by toxins.In the last section, which is devoted to clinical observations, the author demonstrates the existence of a relationship between the posterior segmental lesion and vitamin A deficiency, and shows that punctate corneal opacities result more often from certain virus diseases and malaria than from onchocerciasis. A description follows of various degenerations due to a local nutritional disorder combined with vitamin A deficiency in onchocercal limbitis and anterior uveitis.