How should nystagmus be evaluated and managed?

Evaluation and Management of Nystagmus

Nystagmus evaluation begins with determining whether it is infantile (onset <6 months) or acquired (later onset), as this distinction fundamentally drives the diagnostic workup and need for neuroimaging. 1

Classification and Initial Assessment

Infantile Nystagmus (Onset <6 months)

• Most common causes include albinism, retinal disease, low vision, vision deprivation (congenital cataract), and other retinal disorders 1
• Diagnosed primarily through clinical ophthalmological examination and genetic workup 1
• May occur in fusion maldevelopment syndrome with otherwise normal ocular development 1
• Neuroimaging is typically not required unless red flags are present 1

Acquired Nystagmus (Later Onset)

• Caused by anterior optic pathway lesions (tumors), brainstem/cerebellar lesions, or metabolic diseases (leukodystrophies, mitochondrial diseases) 1
• Neuroimaging is frequently needed, especially with:
  • Late onset nystagmus 1
  • Concurrent neurological symptoms 1
  • Decreased visual acuity 1
  • Asymmetric/unilateral or progressive nystagmus 1

Referral Guidelines

Infants with congenital nystagmus and children with early-onset nystagmus should preferably be managed by a pediatric ophthalmologist 1

Children ≤7 years who are nonverbal or unable to read letters with suspected eye disease should be referred to a pediatric ophthalmologist 1

Neuroimaging Recommendations

When to Order MRI

MRI head without and with IV contrast is the preferred initial imaging modality for children with isolated nystagmus when imaging is indicated 1

In a retrospective review of 148 children with isolated nystagmus, 15.5% had abnormal intracranial findings on MRI, including:

• Abnormal T2 hyperintense signal in white matter (4%) 1
• Chiari 1 malformation (3.4%) 1
• Optic pathway glioma (2%) 1

IV contrast is not required in all cases with isolated nystagmus and can be reserved for children with suspicious lesions on initial MRI 1

Only 2% of patients had intraorbital abnormalities benefiting from dedicated orbital sequences; MRI orbits may be considered if initial brain MRI is suspicious for orbital abnormalities 1

Imaging NOT Recommended

CT head, CT orbits, CTA head, and MRA head have no supporting literature for initial evaluation of isolated nystagmus 1

Special Considerations

Spasmus Nutans

This rare form presents with the triad of nystagmus, head bobbing, and torticollis, appearing at 1-3 years and abating by 5-12 years 1

Cannot be easily differentiated from nystagmus associated with retinal disorders or anterior visual pathway tumors; therefore, thorough neuro-ophthalmological and neuroradiological workup with MRI is necessary 1

Vestibular Nystagmus

May result from peripheral (labyrinth, vestibular nerve) or central vestibular pathway dysfunction 1

Imaging role is primarily to exclude VIII cranial nerve or brainstem lesions 1

Visual Acuity Assessment

Testing Technique in Nystagmus Patients

Binocular visual acuity is especially important in children with nystagmus because it allows compensatory head posture to dampen the nystagmus 1

Monocular occlusion can increase the amplitude of latent nystagmus components, further reducing measured visual acuity 1

For best monocular measurement, use a high-plus sphere as an occluder rather than opaque occlusion 1

Measure both monocular distance acuity and binocular distance and near acuity at 40 cm and at the child's preferred reading distance 1

The preferred method involves linear or crowded optotypes 1

Refractive Management

Cycloplegic retinoscopy is necessary to reveal significant refractive errors that may improve visual acuity 1

Dynamic retinoscopy can assess accommodation and determine if additional near prescription is needed 1

Vision should be checked with and without correction to determine measurable improvement 1

Common Pitfalls

Parents of children with severe visual impairment may report the oculodigital sign (eye pushing), which is a risk factor for keratoconus and periorbital fat atrophy causing enophthalmos 1

Some diseases like Stargardt disease may have subtle fundus changes initially, resulting in delayed diagnosis and unnecessary neurological or psychiatric evaluation 1

Reassure parents that sitting close to television or holding visual targets close does not hurt the eyes—children use their innate accommodation ability 1