Unilateral Benign Gaze–Evoked and Convergence-Evoked Eyelid Nystagmus

Abstract

W e describe a novel case of benign idiopathic unilateral gaze-evoked and convergence-evoked eyelid nystagmus in an otherwise healthy adult. To the best of our knowledge, it is the first such described case.The term "eyelid nystagmus" (also known as "upper lid jerks" and "lid hopping") is a rare phenomenon characterized by a rapid, rhythmic jerking of the upper eyelids and consisting of a fast upward flick, followed by a slower downward drift (1). Pick first used the term in 1916 to describe a nystagmus-like movement of the upper eyelids evoked by convergence in a young woman (2). Pick's patient suffered from multiple sclerosis and spastic quadriparesis (1). Pick hypothesized that lid nystagmus may reflect abnormal excitation within the oculomotor nuclei radiating to the cell bodies that control the levator muscle function. Gaze-evoked lid nystagmus was first reported by Popper, also in 1916 (1).Subsequently, Sanders et al (2) defined the following types of eyelid nystagmus: (1) normal coordinated movements of the lids and eyes during evoked or spontaneous vertical ocular nystagmus; (2) a convergence-evoked lid nystagmus in the absence of ocular nystagmus, as described by Pick; and (3) a synchronous jerking of the upper eyelid with a fast phase of lateral gaze-evoked nystagmus, as described by Popper.Eyelid nystagmus has been associated with numerous pathological conditions, including midbrain tumors, pontine or mesencephalic hemorrhage, Wallenberg syndrome, pontomesencephalic stroke, cerebellar tumor and trauma, brainstem angioma, Miller-Fisher syndrome, and chronic alcohol abuse. Eyelid nystagmus was also described as a sign of drug intoxication (3).A 54-year-old female patient was referred for evaluation of unusual movements of the right eyelid, noted by her orthoptist to whom she was referred because of convergence insufficiency. The patient had never noted the eyelid