The Influence of Fusional Vergence on the Postoperative Ocular Alignment in Intermittent Exotropia

Yang, Hong Seok; Kim, Yang Ho; Lee, Sun Young; Kim, Sang Jin

Abstract

The purpose of this study was to evaluate the influence of fusional vergence on the ocular alignment after surgery in intermittent exotropia. We evaluated fusional convergence and divergence with rotary prism. We examined 44 patients with intermittent exotropia who were followed up postoperatively for at least 6 months from January 1995 to June 1998. The angle of deviation was measured preoperatively, 1 week after surgery and on the last follow-up day. We evaluated the break and recovery point of fusional convergence and divergence at near and far at each measurement of angle of deviation. The subjects were divided into two groups according to the deviation at the last visit : Orthophoria group and Undercorrection group. Orthophoria group was defined as having the deviation equal to or less than 15 delta of exodeviation, and undercorrection group was defined as having the deviation more than 15 delta of exodeviation. In Orthophoria group, break point and recovery point of convergence were 28.07 delta and 26.34 delta at near, 25.52 delta and 22.55 delta at far. The break point and recovery point of divergence were 18.21 delta and 12.38 delta at near, 12.70 delta and 7.73 delta at far. In Undercorrection group, break point and recovery point of convergence were 25.86 delta and 24.71 delta at near, 25.20 delta and 25.80 delta at far. The break point and recovery point of divergence were 18.86 delta and 13.29 delta at near, 17.90 delta and 15.40 delta at far. There was no significant difference between two groups. According to the change from deviation at postoperative 1 week to final deviation, the subjects were divided into four groups. We evaluated the difference of fusional convergence and divergence, according to the change of angle of deviation between postoperative 1 week and the last follow-up day, but there was no significant difference. In conclusion, we can not find any significant influence of fusional vergence on the ocular alignment after surgery in intermittent exotropia.