Strabismus is a condition where there is misalignment of the visual axes of the eyes; it may be latent or manifest and, if manifest, it may be constant or intermittent.
It is a common cause of diplopia (double vision) and visual confusion (seeing different objects in the same place) in adults.
It is an important cause of amblyopia (decreased vision in an anatomically normal eye caused by suppression) in children.
It may be aesthetically obvious to the patient and others, resulting in psychosocial problems.
Evaluation involves a detailed medical history, including a complete ocular history, followed by thorough neurological and ophthalmic examinations.
Treatment is directed at restoring and maintaining ocular alignment, eliminating diplopia or visual confusion, enabling binocular vision, and restoring normal appearance.
If strabismus is secondary to an underlying cause (e.g., abducens nerve [cranial nerve VI] palsy causing esotropia [inwards deviation of one or both eyes]), treatment of this condition is necessary.
Strabismus refers to a misalignment of the eyes. If strabismus develops in adults, it can cause diplopia (double vision) and visual confusion (seeing different objects in the same location), and it is an important cause of amblyopia in children. Whereas normally both eyes fixate (look at) the object of interest, in strabismus one eye fixates and the other (non-fixating eye) is deviated.
The most common types of strabismus are esotropia, where there is inwards deviation, and exotropia, where there is outwards deviation. With hypertropia, there is upwards deviation of the visual axis of one eye relative to the other. With hypotropia, there is downwards deviation of the visual axis of one eye relative to the other.
Strabismus can be classified as comitant (concomitant) or incomitant (non-comitant). With comitant strabismus, the deviation does not vary in size with the direction of gaze. Comitant strabismus makes up most forms of childhood strabismus. With incomitant strabismus, the deviation varies in size with the direction of gaze. Here, the strabismus is often paralytic or restrictive in nature, and may indicate underlying neurological or orbital disease.
History and exam
Key diagnostic factors
- eye misalignment
Other diagnostic factors
- abnormal eye movements
- visual confusion
- intermittent closure of one eye
- cranial nerve palsy
- family history of strabismus
- low birth weight
- maternal smoking during pregnancy
- refractive error
1st investigations to order
- cover test
- simultaneous prism and cover test (SPCT)
- uncover test (UCT)
- alternate prism cover test (APCT)
- Hirschberg test
- Krimsky test
Investigations to consider
- version testing
- duction testing
- forced duction testing
- CT or MRI of orbit
- MRI of brain
- CT chest
Daniel J. Salchow, MD
Pediatric Ophthalmology; Strabismus; Neuro-ophthalmology
DJS declares that he has no competing interests.
Robert B. Avery, MD, PhD
Assistant Professor of Ophthalmology
Department of Surgery
University of New Mexico School of Medicine
RBA declares that he has no competing interests.
Peter Tiffin, BMedSci(Hons), MBBS, FRCOphth
City Hospitals Sunderland
PT declares that he has no competing interests.
Jonathan Smith, MBBS, MRCP, MRCOphth
Specialist Registrar in Ophthalmology
Royal Victoria Infirmary
JS declares that he has no competing interests.
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