When Does Infantile Nystagmus Predict Optic Pathway Glioma?

Optic pathway glioma (OPG) is an uncommon tumor of infancy and childhood. Early recognition is critical to enable timely neuroimaging and treatment; however, this can be challenging. In children presenting symptoms can vary and assessments may be limited. In some, nystagmus may be the main, or occasionally, only presenting clinical sign. We review the clinical characteristics of the nystagmus in these cases and highlight the key elements that should alert the physician to the possibility of OPG and prompt early neuroimaging investigations.

A retrospective study of all patients under 3 years of age, presenting with nystagmus who were subsequently diagnosed with OPG at a tertiary neuro-ophthalmology clinic over a 10-year period. Clinical characteristics of the nystagmus, associated ophthalmic and systemic findings, and magnetic resonance imaging features were reviewed.

One hundred forty pediatric patients were diagnosed with OPG over a 10-year period. Of these 30 patients presented primarily with nystagmus, 27 of them with complete records and were included. In all cases, the OPG involved the optic chiasm. The most consistent diagnostic feature was delayed onset of nystagmus at or after 3 months of age. Additional characteristics included asymmetric or uniocular predominance, dysconjugate nystagmus, multiplanar directionality, and progression or evolution of eye movement patterns over time. Classical localizing patterns such as see-saw nystagmus were less frequent.

Infantile nystagmus with onset beyond 3 months, particularly when accompanied by atypical movement characteristics, should prompt early neuroimaging to exclude OPG. Recognition of these features enables earlier diagnosis in the absence of other clinical signs.