AIM: To explore the application of anterior transposition of inferior oblique muscle with unequal excision in treatment of segregated vertical strabismus with asymmetric inferior oblique hyperfunction.

METHODS: A total of 22 patients(10 males and 12 females, 28 eyes in all)who underwent anterior transposition of the unequal excisional inferior oblique muscle for dissociated vertical deviation with asymmetric inferior oblique muscle overaction were studied retrospectively. The patients were admitted from June 2015 to June 2017,with mean age at 12.32±6.81 years old(ranging from 3 to 28 years old). The binocular vision, the curative effect of DVD, the curative effect of inferior oblique muscle overaction, eye position and compensatory head posture, complications were examined postoperatively, follow-up survey was conducted at 6 to 18mo, meanly at 10.05±3.87mo.

RESULTS: Recovery of binocular vision: 11 cases did not have binocular vision(50%); 6 cases recovered to the first level of binocular vision(27%); 3 cases recovered to the second level of binocular vision(14%); 2 cases recovered to the third level of binocular vision(9%). The curative effect of DVD shows: 17 cases with satisfaction(77%), 5 cases with improvement(23%), and 0 case with no avail. The curative effect of inferior oblique muscle overaction shows: 13 cases with cured(59%), 9 cases with improvement(41%), and 0 case with no avail. Postoperative eye position and compensatory head posture: 1)Horizontal eye position: 1 case of under correction after exotropia correction surgery, 1 case of under correction after esotropia correction surgery, 0 case of overcorrection, 20 cases of correction; 2)Vertical eye position: 13 cases show vertical strabism deviation less than 5^△, 9 cases show vertical strabism deviation between 5^△ to 10^△ meanly at 5.55^△±2.35^△, vertical eye position without overcorrection; 3)Compensatory head posture: 6 cases were disappeared, 1 case was improved. Complications: Mild anti-elevation syndromeoccurred in 1 case, narrowed palpebral fissueoccurred in 1 case, and narrowed quantity less than 1mm.

CONCLUSION: In general, the curative effect of anterior transposition of the unequal excisional inferior oblique muscle for dissociated vertical deviation with asymmetric inferior oblique muscle overactionis satisfactory, standard preoperative examination, individualized surgical design and surgical techniques are necessary.