Nystagmus is a repetitive oscillation of the eyes that is usually rhythmic. Generally, nystagmus is considered as either jerk or pendular. Jerk nystagmus refers to rhythmic back and forth movements in which there is a fast and a slow phase. By convention, nystagmus is described by the direction of the fast phase. Pendular nystagmus refers to rhythmic back and forth movements of the eyes in which the velocity is equal in each direction. The nystagmus may be a mixed combination of both jerk and pendular. This chapter is a clinical-based approach to nystagmus and other texts should be consulted for a detailed pathophysiologic understanding of nystagmus.

Nystagmus may cause visual blurring, but usually does not produce other clinical symptoms or signs. Table 11-1 is a list of the clinical characteristics of congenital nystagmus that allow its differentiation from acquired nystagmus. Table 11-2 lists specific forms of nystagmus that can be localized to particular portions of the central nervous system. Table 11-3 lists those eye movements that can be confused with nystagmus.

Several questions can be asked to better determine the nature of the nystagmus.


Monocular nystagmus is most frequently seen in the following settings.

• Internuclear ophthalmoplegia: A dissociated horizontal gaze nystagmus that occurs in the abducting eye contralateral to the side of the MLF lesion (see p. 269, Chapter 10).

• Heimann-Bielschowsky phenomenon: Long-standing visual loss (from any cause including optic nerve disease, profound amblyopia, dense cataract) can lead to lowfrequency, monocular vertical pendular or jerk nystagmus in the involved eye.

• Spasm nutans: This consists of the triad of nystagmus that is usually vertical, dissociated, rapid, unilateral or bilateral, of small amplitude, and pendular; head nodding and torticollis. It is of unknown etiology and usually starts at 4 to 12 months of age and
disappears by the age of 2. These children should undergo an MRI since chiasmal gliomas have been associated with this eye movement anomaly.

TABLE 11-1. Clinical Characteristics of Congenital Nystagmus

Onset at birth or in the immediate perinatal period

Almost always conjugate and horizontal

Horizontal nystagmus remains horizontal in vertical gaze

It is dampened by convergence and accentuated by fixation

May have a latent component

There is inversion of the optokinetic reflex

There may be head oscillations

Presence of a null point

Absence of oscillopsia

Strabismus is common

Head turns are common

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Jul 14, 2016 | Posted by in OPHTHALMOLOGY | Comments Off on Nystagmus

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