Therapeutic evaluation of lateral rectus super-recession surgery for large angle divergence excess exotropia

Abstract

Background In clinic practice, three or four rectus muscles often are needed to perform operation for the correction of large angle (>50△) exotropia to avoid eye limited abduction due to lateral rectus super-recession.However, recent study reported that lateral rectus super-recession surgery can effectively correct large angle exotropia without remarkable abduction limitation.This outcome still need to be verified in clinical practice. Objective This study was to observe the outcome of bilateral rectus super-recession or medial rectus resection of the combined non-dominant eye for large angle exotropia. Methods A series case study was carried out.Fifty-one patients with intermittent or constant exotropia were enrolled in Tianjin Eye Hospital from May 2013 to October 2014.There were 29 intermittent exotropia and 22 constant exotropia among the 51 patients.Combined with adjustable sutures, bilateral lateral rectus super-recession or medial rectus resection of combined non-dominant eye was performed in all the eyes, and the examination of the anterior segment, fundus, ocular movement and binocular vision were performed before and after surgery.The deviation angle was measured by prism and alternate cover test.The individualized surgery procedure was designed according to medical history, ocular movement, sensory status and deviation angle.The patients were followed-up for at least 6 months.The eye position, ocular movement and binocular sensory function were compared between peoperation and postoperation.This study was approved by the Ethics Committee of Tianjin Eye Hospital.Written informed consents before the operation were obtained from all patient or their parents. Results Thirty-three patients underwent bilateral lateral super-recession and 18 patients underwent bilateral lateral super-recession of the medial rectus resection of the combined non-dominant eye.The mean angle of exotropia for seeing distance of 5 meters was (-70.57±16.46)△(from -52△to -120△) and was (-75.65±16.14)△for seeing near (33 cm) (from -55△to -130△). The mean amount of left eye recession was 8-15 mm ([11.17±1.67]mm) and the right eye recession was 9-15 mm ([11.28±1.62]mm). The medial rectus of the dominant eye was resected by 3-6 mm.At the end of following-up, the mean angle of exotropia for seeing distance was (-3.45±4.20)△(from + 4△to -14△) and was (-5.49±3.96)△for seeing near (from + 4△to -14△). Surgical outcome was effective in 41 patients (80.4%), and 10 patients were undercorrected.The stereopsis of 32 patients improved after surgery, and 18 of 27 patients without preoperative stereopsis function obtained stereopsis after surgery.No ocular motility disorder was found in this group of patients after surgery. Conclusions Bilateral lateral rectus super-recesssion or medial rectus resection of combined non-dominant eye can effectively correct large angle exotropia and reduce the number and amount of surgical muscles without ocular motility disorder. Key words: Ophthalmologic surgical procedure; Exotropia/surgery; Oculomotor muscles/surgery; Treatment outcome; Vision, binocular; Lateral rectus recession; Super-recession; Large angle divergence excess exotropia