The Outcome Of Four-muscle Surgery On The Visual Poor Eye For Treatment Of Large-angle Exotropia

ObjectiveThis study was to observe the application of horizontal rectus recession/resection plus weakening of both obliques on the poorly seeing-eye in large-angle sensory exotropia and assess the postoperation outcome.MethodsThirty eight cases with large angle sensory exotropia(?50PD)who underwent unilateral horizontal rectus recession/resection plus weakening of both obliques from August 2004 to January 2016 were retrospectively reviewed.Before the operation,best corrected visual acuity(BCVA),strabismus angle,eye movement,slit-lamp,and direct fundus examinations were performed.The angle of exotropia is measured by Hirschberg test and prism alternate cover test at the degree of 33 cm.According to the distance of deviation,the lateral rectus recession ranged from5~9mm,the medial rectus resection ranged from 5~11mm,with broking tendon of both obliques.The post-operative eye position/eye movement and Palpebral fissure size were observed with a minimum follow-up of 6 months.Anatomical success was defined as the residual deviation less than 10 prism diopters(PD).Limitation on abduction and adduction in extreme horizontal gaze positions were regarded as ocular motility disorder.Results: 1)The correction rate of 38 patients was 92.1% in the follow-up period of 1 week and was 84.2% in the follow-up of more than 6 months.2)Postoperative long-term observation of 7 patients showed limitation on abduction within 1~3mm.Only one person showed limitation on adversion of 1mm and limitation on abduction of 4mm.The remaining 30 patients with internal and external rotation ranged from +1 to-1.3)At the last follow-up observation,24 patients had no difference in the size of palpebral fissure,and the vertical palpebral fissure width in 12 patients was less than that of the contralateral eye,and the palpebral fissure width in 2 cases decreased by 2 ~ 3mm.3 patients were conscious of the small palpebral fission.Conclusion1)The surgery of horizontal rectus recession/resection plus weakening of both obliques was done on the poorly seeing-eye for patients with large-angle sensory exotropia(? 50PD).The correction rate in alignment at postoperative less than one week and final follow-up periods was 92.1% and 84.2%.2)Four-muscle surgery on the visual poor eye can effectively improve the appearance of patients,and does not cause significant ocular motility disorder.3)There is a slight disparity of vertical palpebral fissure width between the eyes at final follow-up,which had little effect on appearance.Therefore four-muscle surgery on the disadvantage eye is a safe and effective treatment for large-angle sensory exotropia.