CONGENITAL AND lATENT/MANIFEST lATENT NYSTAGMUS: DIAGNOSIS, TREATMENT, FOVEATION, OSCILLOPSIA, AND ACUITY

Congenital (CN) and latent/manifest latent nystagmus (LMLN) are the two most common types of benign infantile nystagmus. They can be distinguished definiti�ely by eye-movement recordings; their clinical characteristics are too similar to allow reliable differential diagnosis. Most treatments for CN, surgical or optical, depend on exploitation of either a gaze-angle or convergence null. Other treatments are emerging that may prove beneficial for those individuals lacking either of these nulls. Early surgical treatment for the strabismus accompanying LMLN may convert the nystagmus into LN only, thereby improving visual acuity (OU). Target foveation is preserved in both CN and LMLN and repetitive (cyc1e-to-cycle) foveation periods appear to be responsible for the absence of oscillopsia in these individuals. The ability to foveate a target for substantial periods of time each cycle, with little variation in eye position or velocity, may result in normal visual acuities despite the nystagmus.