There may be considerable swelling so that the patient cannot for a time see out of the invaded eye. It has been stated that the worms may enter the anterior chamber of the eye but this is questionable.
It is believed that lesions of the cornea and iris may result from the migrations through the body of the Onchocerca volvulus.
Trypanosomiasis.—Eye lesions are quite frequent in this disease these being keratitis, irido-cyclitis or conjunctivitis.
Oedema about the eyes is of importance in diagnosis. Eye lesions seem more common in Rhodesian trypanosomiasis. The atoxyl treatment of the disease may cause optic neuritis and blindness.
Tick Fever.—In the relapsing fever of South Africa iritis has been noted as occasionally occurring.
Yellow Fever.—In the period of onset a feature of the so-called “facies” of the disease is marked injection of the conjunctivae with sensitiveness to the light.
Rush likened it to the eye of a wild animal as contrasted with the less ferocious eye of bilious remittent fever which more resembled that of a domesticated animal. About the third day the earliest manifestation of jaundice presents itself in the ocular conjunctivae.
Ancylostomiasis.—Retinal haemorrhages may occur with marked hookworm anaemia. Stiles notes a fixed stare in hookworm cases, the eye itself somewhat resembling the eye of a fish.
Among other diseases showing ocular manifestations may be mentioned one associated with fibrous nodules in the upper lid due to a larval dibothriocephalid, Sparganum mansoni.