Diffuse unilateral subacute neuroretinitis (DUSN) is a rare condition that occurs in otherwise healthy, often young patients and is due to the presence of a subretinal nematode.

[2] The clinical findings in this disease can be divided into acute and end-stage manifestations: In the acute phase, patients often present with decreased visual acuity, vitritis, papillitis, and crops of gray-white or yellow-white outer retinal lesions.

DUSN may be caused by a helminthic infection with Toxocara canis, Baylisascaris procyonis, or Ancylostoma caninum.

The characteristic lesions are believed to result from a single nematode migrating within the subretinal space.

DUSN has been diagnosed in patients in many countries and climates including America, Brazil, China and India.