Examination of the Measurements of Vertical and Cyclo Deviations in the Patients who have Vertical or Cyclo Strabismus

Purpose: The angles of vertical and cyclo deviations measured by a synoptophore are very important data to decide on the course of treatment. However, we sometimes had the fact that the data by the synoptophore varied according to other measurement methods.So we studied the difference of data between the afferent and centrifugal methods.Subjects: Forty-seven patients with vertical and/or cyclo strabismus, and 23 controls of good visual acuity without strabismus were investigated in this prospective study.Methods: Each subjective angle at their primary position was first measured by the centrifugal method of moving the tube outwards on the synoptophore. Next, the tube of the synoptophore was moved far away from the position corresponding with the centrifugal data and then we measured the subjective angle again by afferent pathway approaching behind far point. We defined the difference in data between two methods as the dissociation.Results: The dissociations of the cyclo deviations were significantly larger than those of vertical deviations between the strabismic subjects and the controls. The vertical dissociations of the strabismic group were significantly larger than those of the control group, especially, those of thyroid-associated ophthalmopathy (TAO) subjects and decompensation superior oblique palsy (decompensate SO palsy) subjects. No significant difference was detected between the strabismic group and the control group.Conclusion: The results suggest that the dissociation of data between the afferent and centrifugal methods may be more associated with the stability of eye position than with the ability of binocular fusion. We recommend that careful measurements of vertical and/or cyclo deviations be performed in patients with strabismus, particularly those with TAO and/or decompensate SO palsy.