Saccadic velocity analysis in patients with divergence paralysis.

Twelve patients with clinical findings of divergence paralysis underwent horizontal saccadic velocity testing. Peak velocities were measured using digitally sampled electro-oculography during 10 degrees, 20 degrees, and 30 degrees saccades. Results were compared with those of 12 age-matched controls. The peak saccadic velocities of each eye in adduction and 10 degrees abduction did not differ from those of age-matched controls (P > .05). The 20 degrees and 30 degrees abducting saccades showed mildly reduced saccadic velocities when compared with controls (P < .05). The finding of only mildly reduced abduction saccadic velocities bilaterally is not consistent with bilateral lateral rectus palsy. The data support the hypothesis that divergence paralysis represents a distinct clinical entity unrelated to abducens nerve paresis and argues for the existence of an active divergence center. We further report the surgical results of five patients who were treated with strabismus surgery. A 4.0 to 6.0 mm bilateral lateral rectus muscle resection corrected 16 to 30 delta of esotropia at distance without resulting in an overcorrection at near. Bilateral lateral rectus muscle resection is an effective therapy for divergence paralysis.