Manifest latent nystagmus of late onset: a case report.

A case of manifest latent nystagmus of late onset in a 13-year-old girl is reported. The nystagmus became manifest during the development of a hypertropia of the left eye. The spontaneous nystagmus was successfully treated by surgical correction of the hypertropia. The observations are discussed with regard to theories on the origin of latent nystagmus.