[Dissociated horizontal deviation--a diagnostic problem in strabismus]

Dissociated horizontal deviation (DHD) is one of the four components of the dissociated strabismus complex which also includes dissociated vertical deviation, dissociated torsional deviation and manifest-latent or latent nystagmus. These dissociated deviations may co-exist with concomitant strabismus (exotropia, esotropia, hyperopia). Sometimes it is difficult to make the difference between dissociated and non-dissociated component of the deviation. We report 3 cases of strabismus and DHD with special emphasis on the diagnostic difficulties and the therapeutic possibility. A careful clinical examination with additional measurement tests makes the difference between DHD and associated tropias. The reversed fixation test is a decisive test for the diagnosis of DHD. The therapeutic approach depends on the type of DHD (uni or bilateral, latent or manifest), the magnitude of the deviation, the fixation behavior and the association of the DHD with exotropia, esotropia or orthotropia.