A Clinical Study: Change of the Eye Position under General Anesthesia

Lim, Sun Taek; Kim, Seong Ju; Park, Yeoung Geol

Abstract

This study was undertaken to evaluate the relationship between eye positions in the awake state and in the surgical plane of anesthesia induced with anesthetics and muscle relaxants in 167 non-paralytic horizontal strabismus patients. All 27 patients with esotropia demonstrated divergence under general anesthesia when compared with their pre-anesthetized state. In 140 patients with exotropia, 107 patients(76.4%) demonstrated convergence under general anesthesia, 6 patients(4.3%) demonstrated divergence, 27 patients demonstrated no change of the eye position. A statistically significant relationship was found between the preanesthetized position of the eyes(P) and the eye position under general anesthesia(A). The relationship is linear and can be written as the approximate regression fomula: A=0.44P+6.34, R=0.73(p<0.01). When surgical success was defined as an eso- or exodeviation within 10 delta of orthotropia at postoperative 12 weeks, final success rate revealed statistically significant difference between the following two groups of exotropic patients(p<0.05). The patients whose amount of vergence were under 15 delta had a success rate of 96.6%, while those over 16 delta had a success rate of 86.3%. In esotropia, surgical success was not satisfactory in patients whose amount of deviation were over 41 delta. These results suggest the significant relationship between eye positions in the awake state and those under general anesthesia, which could be clinically applied in deciding the surgical amount and predkting the success of strabismus surgery.