An investigation into the mechanisms causing antipodean strabismus.

Background: Antipodean strabismus is a rare clinical entity in which a patient manifests an esotropia when fixating with one eye and an exotropia when fixating with the other eye. It has been described in the settings of marked uncorrected anisometropia, dissociated strabismus or combinations of paresis, and mechanical restriction of eye movement.

Methods: A retrospective review of four patients with antipodean strabismus.

Results: All patients demonstrated a unique and uncommon pattern in which there was esotropia with one eye fixating and exotropia with the other eye fixating. None of the patients demonstrated anisometropia or signs of dissociated horizontal deviation. One patient developed antipodean strabismus after prior surgery to correct a traumatic sixth nerve palsy. Another patient had an associated pseudotumor cerebri. The other two patients had no pertinent medical history and, on clinical examination, demonstrated markedly asymmetric accommodative convergence/accommodation (AC/A) ratios.

Conclusions: Antipodean strabismus is an atypical heterotropia, which can be associated with a variety of clinical findings. This article demonstrates the uniqueness of this clinical entity and illustrates the first association of this pattern with a markedly asymmetric AC/A ratio.