Acquired Nystagmus Differential Diagnoses

Updated: Jun 22, 2021
  • Author: Huy D Nguyen, MD, MBA; Chief Editor: Edsel B Ing, MD, MPH, FRCSC, PhD, MA  more...
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DDx

Diagnostic Considerations

Congenital nystagmus (infantile nystagmus)

Infantile, or congenital, nystagmus typically presents between 2-4 months of life when visual fixation normally develops and is distinct from acquired nystagmus in that it is conjugate, has mixed jerk and pendular waveforms, has a null point and a lack of oscillopsia. [18]  Visual loss, if present, is stable and not progressive. In infants who present with nystagmus, the most important distinction to make is between congenital nystagmus and spasmus nutans. [18]  Congenital nystagmus classically present as a horizontal nystagmus with a pendular waveform but may also be torsional or veritcal (rare). [18]  Congenital nystagmus may be sub-classified into congenital motor nystagmus (presents with relatively normal vision, normal fundus, and normal neurological examinations) and congenital sensory nystagmus (presents with poor vision). [18]  An infant that presents with a nystagmus must undergo a careful assessment of visual acuity and fundus appearance to classify their congenital nystagmus. [18]  If the nystagmus is caused by a retinal disorder, it typically presents with moderately to severely diminished vision (congenital sensory nystagmus), paradoxical pupil constriction when the light is turned off, oculodigital reflex, photophobia or high myopia. [18]  Foveal hypoplasia, along with transillumination of the retina with a slit lamp can be used to identify ocular albinism. [18]  In those with congenital sensory nystagmus or those whose examination results is inconclusive, MRI imaging of the brain, electroretinography and OCT would likely provide aid in diagnosis. [18]  If the patient presents with a congenital motor nystagmus but is otherwise normal, only close follow up is necessary. [18]  The presence of a pale optic disk, a history of progressive visual loss, or unilateral vertical nystagmus should suggest that the nystagmus is acquired and possibly due to a neoplasm involving the visual system. [18]  Such patients require MRI neuroimaging. [18]

Voluntary nystagmus

Voluntary nystagmus refers to a series of rapidly alternating horizontal saccades that occur usually in bursts of 5-10 seconds, are produced by individuals for gain or amusement, and may be seen in families. [18]  The nystagmus itself is a high frequency (3-42Hz), low amplitude back and fro oscillation that cannot be sustained. [18]  Patients with voluntary nystagmus complain of blurry vision and oscillopsia, and their ocular oscillation may be accompanied by lid fluttering and squinting. [18]  Voluntary oscillations may be interrupted by having the patient pursue a visual target or with distraction. [18]

Convergence retraction nystagmoid movements

Although not a true nystagmus because it lacks slow phases and is just opposing saccades, it is a potentially localizing eye movement disorder similar to nystagmus. Convergence retraction nystagmus may be elicited by having the patient look up quickly or by moving an optokinetic tape downward. [18]  The deficit in upgaze results in increased signal to other muscles, including the dominant medial recti, that manifest as a convergence and co-contractions of muscles that manifest as retraction. It is a sign of pretectal dysfunction and is usually accompanied by other neurological symptoms like upgaze palsy, pupillary light dissociation, and eyelid retraction. [18]  Dorsal midbrain lesions may cause convergence retraction nystagmoid movements. [18]

Thyroid associated ophthalmopathy may present with eyelid retractions, decreased upgaze and globe retractions which can mimic convergence retraction nystagmus. [18]  Lack of pupillary abnormalities in addition to the presence of exophthalmos, conjunctival injections, eyelid edema and positive forced ductions distinguish the two pathologies. [18]

 

Differential Diagnoses