Walsh & Hoyt: Roundworms (Nematodes)

Roundworms, also called nematodes (from the Greek words nema, meaning ""thread,"" and eidos, meaning ""form""), are nonsegmented, bilaterally symmetric, and cylindric or filiform, with a body cavity and rounded or pointed ends. They vary considerably in size, although the male usually is smaller than the female. A variety of roundworms is responsible for human disease, and many of these organisms also cause neuro-ophthalmologic manifestations by virtue of their effects on the CNS and the ocular structures. The nematodes of particular neuro-ophthalmologic significance are Angiostrongylus cantonensis, Gnathostoma spinigerum, Loa loa, Onchocerca volvulus, Strongyloides stercoralis, Toxocara species, and Trichinella spiralis.