Which physical findings are characteristic of congenital nystagmus?

Updated: Oct 08, 2019
  • Author: Mark Ventocilla, OD, FAAO; Chief Editor: Edsel Ing, MD, MPH, FRCSC  more...
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Answer

Both sensory deficit nystagmus and idiopathic infantile nystagmus are almost always bilateral, symmetric, and conjugate. [4]

Eye movements usually are horizontal and remain so during vertical gaze (horizontal uniplanar) rather than changing to a gaze-evoked vertical nystagmus. The nystagmus disappears during sleep.

The nystagmus movements may be pendular or jerk in nature. The nystagmus may be intermittent or continuous. The congenital nystagmus patient may have good vision or poor vision. There is no oscillopsia. There may be an inversion of the optokinetic reflex.

Nystagmus intensity (a product of the frequency and amplitude) often increases with fixation effort, attention, or anxiety, and diminishes with convergence.

Various waveforms have been described. Both pendular and jerk types have been documented to occur in idiopathic infantile and sensory deficit nystagmus. Nystagmus associated with albinism has characteristics similar to idiopathic infantile nystagmus. Latent and manifest latent nystagmus always are jerk-type with the fast phase in the direction of the fixing eye and decreasing velocity of the slow phase; the nystagmus is larger in the amblyopic or nonfixing eye, and amplitude decreases in adduction. Spasmus nutans classically is a triad of nystagmus, head nodding, and torticollis. The nystagmus is disconjugate, high frequency, small amplitude, pendular, and intermittent. It is suppressed with head nodding. A head tilt often is present. Spasmus nutans often disappears after a few years.

The hallmark of idiopathic infantile nystagmus is a gaze-dependent, variable intensity resulting in a "null zone" where nystagmus is least marked and visual acuity is maximized. This often corresponds to adoption of an anomalous head posture and is frequently the stated reason for referral.

In patients with nystagmus, visual acuity should be measured by fogging the contralateral eye with a +4 to +10 hyperopic lens over the patient's normal refractive error.

Slit-lamp examination should be performed to exclude iris transillumination defect. Funduscopy should be used to document the presence or absence of foveal hypoplasia, optic disc morphology, and any lack of fundus pigmentation.


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