Torticollis is an abnormal head position (AHP): head turn, chin-up or chin-down, tilt, or any combination of these. Ocular torticollis, as opposed to nonocular torticollis, results from strabismus or other eye conditions; see Table 7-2 for the differential diagnosis of both ocular and nonocular torticollis.
Early diagnosis and correction of ocular conditions resulting in torticollis is important because prolonged AHP (primarily head tilt) in children can cause facial asymmetry or secondary musculoskeletal changes. Note, however, that facial asymmetry coexisting with head tilt is not always caused by the head tilt. For example, unicoronal craniosynostosis can result in strabismus with ocular torticollis and also directly cause facial asymmetry independent of the torticollis.
Sometimes an AHP and associated ocular abnormality simply have a shared underlying cause (eg, ocular tilt reaction), but more often, the AHP compensates for the ocular condition.
Table 7-2 Differential Diagnosis of Torticollis
Incomitant strabismus (eg, superior oblique palsy, Duane retraction syndrome, Brown syndrome, blowout fractures, thyroid eye disease) can cause an AHP that improves binocularity. Chin-up positioning in unilateral ptosis likewise enables binocularity. In rare cases, patients with superior oblique palsy show paradoxical head tilt to the wrong side, possibly to increase the separation between diplopic images when fusion is not possible.
In infantile nystagmus syndrome (congenital motor or sensory nystagmus) with a null point away from primary position, an AHP improves vision. In fusion maldevelopment nystagmus syndrome (manifest latent nystagmus), vision improves with an AHP that brings the fixating eye into adduction. With bilateral duction deficits (eg, congenital fibrosis of extraocular muscles) or bilateral ptosis, an AHP may be needed for foveation. Refractive errors may also cause an AHP.
Finally, monocular individuals and patients with homonymous hemianopia may have a variable head turn toward their blind side, perhaps to better center (relative to the body) the total field of view that is accessible through eye movements.
Diagnostic evaluation of ocular torticollis
To identify ocular causes of an AHP, motility testing should be done, with particular attention to gaze positions opposite those favored. Nystagmus is usually obvious, but subtle nystagmus may be visible only during slit-lamp or fundus examination. Fundus examination may reveal extorsion suggestive of superior oblique palsy, or conjugate torsion (extorsion in one eye and intorsion in the other), as seen in the ocular tilt reaction. If placing the patient in the supine position eliminates the head tilt, a musculoskeletal etiology is unlikely. If monocular occlusion eliminates the AHP, the torticollis probably serves binocular fusion.
Excerpted from BCSC 2020-2021 series: Section 10 - Glaucoma. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.