Monocular nystagmus in an eye with long-standing poor vision is often referred to as the Heimann-Bielschowsky phenomenon. This phenomenon may occur in patients with poor vision from a variety of underlying etiologies, including optic neuropathy and amblyopia. Onset may occur in adulthood with highly asymmetric vision loss and may not remit even if the visual problem (eg, dense cataract) is corrected. The nystagmus is characterized by intermittent, monocular, vertical, slow, pendular eye movements of low frequency and variable amplitude. Workup is directed toward determining the etiology of the visual loss. The etiology may be obvious on ophthalmologic examination, requiring no additional diagnostic testing (eg, in an infant with unilateral microphthalmos). However, monocular vertical nystagmus in an infant with a relative afferent pupillary defect and optic nerve head atrophy suggests an optic nerve or chiasmal tumor (glioma) and therefore warrants neuroimaging. Symptomatic oscillopsia is uncommon and can be treated with gabapentin. Strabismus surgery can improve appearance.
Excerpted from BCSC 2020-2021 series: Section 5 - Neuro-Ophthalmology. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.