strabismus
Strabismus is a condition in which the visual axes are misaligned by a deviation too great for sensory fusion within Panum's fusional areas.1 Its types are esotropia, exotropia, hypertropia and hypotropia, and its synonyms include heterotropia, turning eye, squint and cast.1
Neuromuscular anomalies of the eyes fall into two classes, latent deviations called heterophorias and manifest deviations called heterotropias, and strabismus is the generic name for the manifest class.2 Strabismus is either comitant or incomitant.2 In comitant strabismus the deviation is the same in all directions of gaze for a given fixation distance, within physiologic limits.2 In incomitant strabismus one or more extraocular muscles underact or are paralyzed, and the deviation is larger with the eyes turned in the direction of action of the affected muscle.2
If strabismus is reported or detected, the history should establish how long it has been present and whether it is constant or intermittent.3
Sources (7)
- Pickwell's Binocular Vision Anomalies, glossary
- von Noorden and Campos, Binocular Vision and Ocular Motility, ch. 8
- Pickwell's Binocular Vision Anomalies, ch. 2
- American Academy of Ophthalmology. 2020. Strabismus Terminology. [online] Available at: <https://www.aao.org/education/bcscsnippetdetail.aspx?id=ce9b9c03-0bc8-4a63-8e51-09334c399fd7> [Accessed 6 May 2024].
- Noorden, G.K. and Campos, E.C. 2002. Binocular vision and ocular motility: theory and management of strabismus. 6th ed. St. Louis: Mosby.
- Rutstein, R. and Daum, K. 1997. Anomalies of Binocular Vision: Diagnosis & Management. St. Louis: Mosby.
- Von Noorden, G.K. and Campos, E.C. 2002. Binocular vision and ocular motility: theory and management of strabismus. 6th ed. St. Louis: Mosby.
Reviewed October 2026