Surgical management of skew deviation

Skew deviation: clinical updates for ophthalmologists

PURPOSE OF REVIEW

This article discusses the current approach in diagnosing skew deviation, as well as recent findings in the lesion localization.

RECENT FINDINGS

Skew deviation can be defined as vertical misalignment of the eyes that does not map to any of cyclovertical muscles, in association with neurologic symptoms and signs and with posterior fossa lesion. It can be differentiated from trochlear nerve palsy by the direction of ocular torsion and the change in the degree of vertical deviation with upright and supine head position. It is commonly caused by ischemia of the posterior paramedian pons, medial thalamus, or cerebellum. Other less common mechanism being demyelinating lesion, mass effect, infection, hemorrhage, or intracranial hypertension. When the vestibular nuclei are involved, skew deviation may occur with acute vestibular syndrome. Ground-in or Fresnel prism may alleviate diplopia in relatively small vertical deviation; however, patient with larger deviation or with the presence of ocular torsion may benefit from surgery of the cyclovertical muscles.

SUMMARY

Skew deviation can be appropriately diagnosed from the nature of the ocular torsion and the vertical deviation, along with the presence of lesion involving posterior paramedian pons and/or medial thalamus.

Surgical treatment of vertical ocular motility disorders of supranuclear origin

Vertical ocular motility disorders of supranuclear origin can be congenital or acquired later in life. They produce complex forms of strabismus that require specialized surgical management to restore ocular alignment, eliminate torticollis, treat diplopia, and restore normal lid position. For each condition, surgical management must be individualized to address multiple impediments to fusion. This article outlines the surgical management of three common types of supranuclear vertical strabismus.

Torsional augmentation for the treatment of lateropulsion and torticollis in partial ocular tilt reaction

PURPOSE

We describe a new surgical treatment for lateropulsion and torticollis arising from an ocular tilt reaction.

METHODS

Visual sensory parameters and postural abnormalities were retrospectively reviewed in a patient with a partial ocular tilt reaction who was treated with horizontal transposition of the vertical rectus muscles to surgically augment preexisting binocular torsion.

RESULTS

Torsional augmentation eliminated the sensation of lateropulsion and produced almost complete resolution of her torticollis and associated body tilt.

CONCLUSIONS

Binocular torsional augmentation can be used to reduce both lateropulsion and torticollis in the setting of an ocular tilt reaction.

Skew Deviation Revisited

Skew deviation is a vertical misalignment of the eyes caused by damage to prenuclear vestibular input to ocular motor nuclei. The resultant vertical ocular deviation is relatively comitant in nature, and is usually seen in the context of brainstem or cerebellar injury from stroke, multiple sclerosis, or trauma. Skew deviation is usually accompanied by binocular torsion, torticollis, and a tilt in the subjective visual vertical. This constellation of findings has been termed the ocular tilt reaction. In the past two decades, a clinical localizing value for skew deviation has been assigned, and a cogent vestibular mechanism for comitant and incomitant variants of skew deviation has been proposed. Our understanding of skew deviation as a manifestation of central otolithic dysfunction in different planes of three-dimensional space is evolving. The similar spectrum of vertical ocular deviations arising in patients with congenital strabismus may further expand the nosology of skew deviation to include vergence abnormalities caused by the effects of early binocular visual imbalance on the developing visual system.