Ectoparasites are organisms that live on the skin of a host, from which they derive their sustenance. The phylum Arthropoda includes the two-winged, or dipterous, flies. The larvae or maggots of these flies may invade the living or necrotic tissue of animals and humans, producing myiasis. Multiple dipterous flies are thought to be capable of producing ocular myiasis. It is thought that the larvae are embedded in the eye, that they burrow directly through the sclera and then under the retina. Typically, they leave asymptomatic tracks throughout the fundus, but a number of cases of destructive endophthalmitis have been reported, particularly from Scandinavia.
