The Effect of Perceptual Learning in Reconstructing Stereopsis of Postoperative Comitant Exotropia

Abstract

Objective: To observe the effect of perceptual learning in reconstructing stereopsis of postoperative comitant exotropia. Methods: In this prospective study, 23 postoperative exotropic patients who underwent surgery from August 2009 to August 2011 at the First Affiliated Hospital of Anhui Medical University were recruited. By three months after surgery, all patients were aligned but did not achieve normal stereopsis when examined by the Titmus stereo test. Patients were trained by a perceptual learning method based on disparity discrimination. Disparity discriminating accuracy and stereoacuity were measured before and after training. The data were analyzed using paired t-test. Results: Two patients were excluded due to poor fusion. The average training time was 6.9 ± 3.8 days. After training, stereoacuity was significantly improved in all 21 patients (t=8.228, P<0.001). The disparity discriminating accuracy test showed that under disparities of 320″, 440″, and 580″, the accuracies were improved after training (t=-3.102, P=0.01; t=-2.360, P=0.02; t=-2.177, P=0.03 respectively). Conclusions: Perceptual learning can be used in reconstructing stereopsis for postoperative exotropic patients, and the effect can be maintained. However, the exact mechanism by which the reconstruction of stereopsis occurs need further research. Key words: perceptual learning; exotropia; stereopsis