Improvement In Fusion And Stereopsis Following Surgery For Adolescents With Intermittent Exotropia

Objective:To evaluate fusion stereopsis in patients with intermittent exotropia(XT) before and after strabismus operation.Methods:53 patients(mean age: 11.8 years, range:5 to 25 years) with XT were enrolled.Fusion was measured with the Worth four dot test. Near stereopsis was examined with Titmus and stereoscopic test charts(created in China by Shao-Ming Yan). Distance stereopsis was tested with random-dot stereograms produced by Tianjin Eye Hospital. All patients were completed the tests preoperatively and 2 and 6 weeks postoperatively.Results:Near stereopsis was significantly improved after 6 weeks in Titmus as well as stereoscopic test charts(P<.05). Among 53 patients, the percentage of distance stereoscopic improvement was 49% after 2 weeks and 77% after 6 weeks compared to 13% preoperatively. Six weeks postoperatively, Thirty-six(68%) patients achieved 60 arcsec.Fifty(94%) demonstrated peripheral fusion and only 21(39.6%) demonstrated central fusion preoperatively. Six weeks postoperatively, all patients exhibited peripheral fusion and 52(98.1%) demonstrated central fusion. Central fusion in patients with XT significantly increased after 6 weeks(P<.001).Conclusions:Patients with XT have good near stereoacuity preoperatively and postoperatively.Even if surgery is postponed until adolescence, distance stereopsis can still be recovered.Surgical intervention can restore central fusion and stereoacuity in patients with intermittent exotropia.