Clinical profile and surgical outcomes of Duane syndrome with primary position hypertropia with or without coexisting horizontal deviation.

Purpose: To report the clinical presentation and surgical outcomes of patients with Duane syndrome with primary position hypertropia, with or without coexisting horizontal deviation.

Methods: We retrospectively reviewed records of patients diagnosed with Duane syndrome with vertical and associated horizontal deviations from January 2008 to July 2017. We collected data regarding patient age, gender, refractive error, presence or absence of amblyopia and history of strabismus surgery, as well as clinical subtype of Duane syndrome, abnormal head posture, measurement of horizontal and vertical deviation, and outcomes of strabismus surgery. Success was defined as post-operative primary position hypertropia <4 prism diopters (PD) and horizontal deviation <10 PD.

Results: During this period, a total of 590 patients with Duane syndrome were seen. Of these, 18 patients (10 males and 8 females) met the study criteria, giving a prevalence of 3%. Median age was 21 years. Seventy-eight percent cases had type III Duane syndrome. Ten patients underwent surgical correction, of which four patients had to undergo a second procedure after a median of 19 months. Sixty-seven percent of the patients had associated primary position exotropia with median deviation of 30 PD. Seventeen percent of patients had only primary position hypertropia with median 10 PD. All patients had overshoots. Primary position horizontal deviation improved from 25 PD to orthotropia, and vertical deviation improved from 10 PD to orthotropia. Lateral rectus recession with Y split was the most frequent procedure performed, and we saw a median reduction of 10 PD hypertropia with this procedure. Median follow-up period was 13 months. Success was achieved in 60% of the patients who underwent surgery. Given the small sample size, it was difficult to compare the efficacy of different procedures.

Conclusion: Current study suggests that primary position vertical deviation might exist in 3% of patients with Duane syndrome. All patients had associated overshoots, which were predominantly of a mixed mechanism. Forty percent of the patients needed re-surgery. Well-designed, prospective possibly multicentric studies are necessary to understand the mechanism of overshoot, and consequently the primary position hypertropia to plan accurate management for these patients.