PURPOSE:

To determine the differences in various epidemiologic and clinical characteristics among types I, II, and III of unilateral Duane syndrome and between unilateral and bilateral Duane syndrome.

METHODS:

A retrospective chart review of 331 patients with the Duane syndrome (291 unilateral and 40 bilateral) was performed. Various characteristics studied included sex, age at presentation, laterality, manifest primary position horizontal deviation, upshoot and downshoot, amblyopia, and associated ocular and systemic abnormalities.

RESULTS:

Unilateral types I and III Duane syndrome were more common in the left eye and in female patients, whereas type II had no such predilection. The mean age at presentation was significantly greater in type III patients. Type I patients had an almost-equal frequency of esotropia and exotropia, type II had exotropia, and type III had exotropia more commonly than esotropia. The upshoots and downshoots were more common in types II and III. There was no difference in amblyopia among various types of Duane syndrome. Associated ocular abnormalities were more common in types I and III, and systemic abnormalities were more common in type I. A manifest primary position horizontal deviation was more common in bilateral Duane syndrome. Exotropia was more common in unilateral cases, whereas esotropia was more common in bilateral cases.

CONCLUSION:

Unilateral types I, II, and III Duane syndrome differ in the mean age at presentation, primary position horizontal deviation, upshoot and downshoot, and associated ocular and systemic abnormalities. Bilateral Duane syndrome differs from the unilateral only in the primary position horizontal deviation.