Diffuse unilateral subacute neuroretinitis (DUSN) is a rare form of chorioretinitis caused by retinal infestation by nematode larvae. Definitive diagnosis requires visualization of a motile nematode, but this can be challenging because the nematode is small, translucent, and usually motionless with overlying media opacity from cellular inflammation. The authors describe a case of DUSN in which widefield swept-source optical coherence tomography angiography was used to localize a midperipheral intraretinal nematode facilitating subsequent clinical observation of movement. Inflammation resolved after focal laser photocoagulation of the nematode with recovery of visual acuity to 20/20. [Ophthalmic Surg Lasers Imaging Retina. 2021;52:345-349.].