A 60-year-old man had worsening vertical oscillopsia and was ultimately diagnosed with idiopathic downbeat nystagmus. The nystagmus was subtle and more noticeable with slit-lamp magnification (video 1 at Neurology.org), but direct ophthalmoscopy revealed marked (upbeat) nystagmus of the fundus (video 2).
Direct ophthalmoscopes are ubiquitous and have 15× magnifying power. Their use in detecting and magnifying subtle nystagmus was first described by Zee.1 Because the optic disc sits behind the axis of rotation of the globe, its motion is opposite the front of the eye; therefore, our patient's subtle downbeat nystagmus appears as obvious upbeat nystagmus of the fundus.
Supplementary Material
Footnotes
Supplemental data at Neurology.org
Download teaching slides: Neurology.org
STUDY FUNDING
No targeted funding reported.
DISCLOSURE
The author reports no disclosures relevant to the manuscript. Go to Neurology.org for full disclosures.
REFERENCE
- 1.Zee DS. Ophthalmoscopy in examination of patients with vestibular disorders. Ann Neurol 1978;3:373–374. [DOI] [PubMed] [Google Scholar]
Associated Data
This section collects any data citations, data availability statements, or supplementary materials included in this article.