Electroretinography in congenital idiopathic nystagmus.

Ganzfeld electroretinograms were recorded from 105 consecutive patients clinically believed to have congenital idiopathic nystagmus. Retinal disease causing congenital nystagmus was diagnosed in 59 patients (56%). Electroretinographic evaluation of children with nystagmus and apparently normal eyes has both diagnostic and prognostic value. In patients with congenital nystagmus with a normal ocular examination, a diagnosis of congenital idiopathic nystagmus cannot be inferred without electroretinographic evidence of normal retinal function.