Background: A syndrome has been described in which some patients with uniocular infantile blindness have a horizontal nystagmus in their contralateral, structurally sound eye. This nystagmus has the characteristics of latent nystagmus. This study investigated the hypothesis that this syndrome is present when infantile monocular blindness occurs in patients who are genetically predisposed to congenital strabismus. In these patients, nystagmus, which would be latent, is made manifest by media opacity or suppression acting as an occluder.
Patients: 1 prospectively studied all patients with this syndrome whom I examined between 1982 and 1994. Evaluation included a careful investigation of whether there was a family history of congenital strabismus. Three patients underwent electro-oculography.
Results: The series consisted of 24 patients with the syndrome of infantile uniocular blindness with bilateral nystagmus, of whom 14 (58%) had a family history of congenital strabismus. In a consecutive series of 50 patients with monocular congenital blindness caused by opacity of the ocular media but not manifesting nystagmus of the contralateral eye, only three patients (6%) had a family history of congenital strabismus. This difference was statistically significant (P < .01).
Conclusions: It appears likely that the syndrome of monocular infantile blindness with bilateral nystagmus represents a manifest nystagmus of the latent type in patients who have inherited a genetic predisposition for congenital strabismus. In these patients, the monocular blindness (opacity of the media or suppression) acts as an occluder, making manifest what would have been latent nystagmus.