A-Pattern Esotropia and Exotropia Clinical Presentation

Updated: Apr 15, 2018
  • Author: James L Plotnik, MD, FACS; Chief Editor: Hampton Roy, Sr, MD  more...
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Presentation

History

Inward or outward deviation of the eyes is the most common presenting problem.

The vertical variation in the magnitude of the horizontal deviation may not be obvious to the parents or the patient.

A head tilt (chin up or down) may be present, as the individual adopts a head posture that allows the eyes to remain in the position of minimal deviation. This compensatory maneuver minimizes diplopia and allows binocular viewing.

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Physical

Measurements of the amplitude of horizontal deviation are obtained by prism and alternate cover testing in primary position and, then, with the eyes 25° in upgaze and 25° in downgaze. Measurements should be made while the patient wears proper refractive correction and fixates on an accommodative target at distance. Note any underaction and overaction of the oblique muscles on versions and any compensatory abnormal head posture. Examine the palpebral fissure configuration (presence of a mongoloid appearance).

Clinical findings of A-pattern esotropia are as follows:

  • Esotropia increases in midline upgaze and decreases in midline downgaze.

  • Eyes may be straight in downgaze and primary gaze.

  • Patients may demonstrate a chin-up posture, a compensatory maneuver that requires the eyes to be in downgaze for straight-ahead viewing. This posture places the eyes in the position of gaze where less inward deviation (more divergence) of the eyes occurs, possibly allowing single binocular vision.

Clinical findings of A-pattern exotropia are as follows:

  • Exotropia increases in midline downgaze and decreases in midline upgaze.

  • Eyes may be straight in upgaze and primary gaze.

  • Patients may demonstrate a chin-down posture, a compensatory maneuver that requires the eyes to be in upgaze for straight-ahead viewing. This posture places the eyes in the position of gaze where less outward deviation (more convergence) of the eyes occurs, possibly allowing single binocular vision.

Patients with A-patterns may manifest signs of superior oblique overaction, including overdepression in adduction, incyclotorsion of the involved eye(s), and/or associated vertical strabismus. [10]

  • Patients may demonstrate a tight superior oblique muscle on forced duction testing.

  • Most patients with congenital overaction of the superior oblique muscles do not manifest subjective complaints of torsion; instead, they manifest objective evidence of intorsion by indirect ophthalmoscopy. This may be most noticeable in downgaze.

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Causes

See Pathophysiology.

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