• Diffuse unilateral subacute neuroretinitis (DUSN) is a clinical syndrome characterized early by visual loss, vitritis, papillitis, and recurrent crops of graywhite retinal lesions and later by progressive visual loss, optic atrophy, retinal vessel narrowing, and diffuse pigment epithelial degeneration. Evidence is presented that it is caused by a nematode that is probably not Toxocara canis; that at least two nematodes of different sizes are involved; that there are at least two endemic areas for the disease; that these areas are related to the size of the nematode; that the nematode may remain viable in the eye for three years or longer and cause progressive ocular damage; that thiabendazole and diethylcarbamazine citrate are ineffective therapeutically; and that photocoagulation is effective in destroying the nematode. Surgical excision of the nematode was attempted in two patients.
J. Donald M. Gass, Robert A. Braunstein. Further Observations Concerning the Diffuse Unilateral Subacute Neuroretinitis Syndrome. Arch Ophthalmol. 1983;101(11):1689–1697. doi:10.1001/archopht.1983.01040020691004