The nystagmus blockage syndrome. Congenital nystagmus, manifest latent nystagmus, or both?

Abstract

We have studied, by quantitative oculography, a patient with the nystagmus blockage syndrome (NBS), and two patients with a similar disorder of eye movements that might be mistaken clinically for NBS. Our recordings revealed two distinctly different abnormalities present in a single patient with NBS. Our NBS patient exhibited congenital nystagmus (CN) waveforms when viewing at distance; the CN did not damp with convergence on a near target. When the patient allowed one eye to become esotropic, however, the nystagmus damped considerably and abruptly changed from CN to manifest latent nystagmus (MLN). This peculiar transition from CN to MLN has not been described previously. The appearance of ..