Anomalous head posturing in essential infantile esotropia: a hypothesis

Abstract

1This editorial presents our understanding of why a child with infantile esotropia syndrome may manifest a visually directed anomalous head posture (AHP). Many aspects of essential infantile esotropia (EIE) or infantile esotropia syn-drome remain controversial and ill-defined (1). The recent National Eye Institute, National Institutes of Health, USA–sponsored Classification of Eye Movement Abnormalities and Strabismus (CEMAS) workshop and document has at-tempted to consolidate its definition (2). Table I presents the CEMAS description of EIE.Torticollis in childhood is most commonly the result of ab-normalities of the central nervous system, the ocular motor system, or the neck musculature. Head posturing associ-ated with abnormalities of the ocular motor system is usu-ally compensatory. The visual purpose of head posturing serves to enhance bifoveal fixation, singular binocular vi-sion, or visual acuity. The ocular etiologies of anomalous head posture include strabismus, nystagmus, refractive errors, dissociated ocular deviations, and visual pathway obstruction (e.g., lid, corneal, lens, and vitreous anoma-lies). Although clinical differentiation of these disorders is accurately accomplished after a thorough history and ophthalmic examination, the etiology of anomalous head posture is often elusive in patients with a combination of strabismus and nystagmus. Children with nystagmus will have anomalous head posture due to multiple causes. A “gaze null” is a position of one or both eyes with respect to the orbit where the nystagmus intensity is the least and vision is the best and is usually associated with infantile nystagmus syndrome or more rarely, forms of acquired nystagmus with an eccentric gaze null position, e.g., gaze evoked, upbeat, and downbeat nystagmus. An “adduction null” is a position of a preferred eye in adduction charac-