The Effect of Cyclotorsion on the Score of the Binocular Field of Single Vision in Patients with Superior Oblique Paresis

Abstract

We plotted fields of binocular single vision (BSV) for each of 19 patients with superior oblique paresis (17 unilateral and two bilateral) who complained of diplopia to determine whether BSV scores obtained with fusion (cross) and non-fusion (spot) targets yield clinically significant differences that could be correlated with torsional changes from primary position to down gaze. Both fields were scored with a template weighted to primary position and down gaze. Excyclotorsion was measured in primary position and down gaze for each patient. Seven patients who had an increase in torsion from primary position to down gaze showed no clinically significant differences in BSV scores derived from the two targets. Three patients who had clinically significant changes in BSV scores had no changes in torsion from primary position to down gaze. We conclude that factors in addition to positional torsion changes influence BSV field scores when they are plotted with a fusion target rather than a non-fusion target.

• binocular visual field
• cyclotorsion
• diplopia
• fusion
• fusional amplitudes
• superior oblique paresis