Comparison of Surgical Results between Bilateral and Unilateral Lateral Rectus Recession in 20~25 Prism Diopters Intermittent Exotropia

ABSTRACT

PURPOSE: To compare the postoperative results of unilateral lateral rectus recession with bilateral lateral rectus recession between 20 prism diopters (PD) and 25 PD intermittent exotropia for basic type. METHODS: We analyzed retrospectively the data of 27 patients underwent unilateral lateral rectus recession and 38 patients underwent bilateral lateral rectus recession with 20 PD and 25 PD intermittent exotropia for basic type from June 1996 to May 2000 at the Department of Ophthalmology of Chonnam National University Hospital. RESULTS: There were 10 cases (37.0%) in unilateral group and 8 cases (21.1%) in bilateral group showing undercorrection in the amount of deviation more than 10 PD and 2 cases (5.3%) in bilateral group showing overcorrection in the amount of deviation more than 10 PD, and there was no overcorrection in unilateral group. There was a tendency of recurrence of exotropia during the first postoperative month, but the alignment after 1 month postoperative was not much different from the alignment at the last follow-up. The mean amount of correction after surgery was 13.78+/-7.65 PD (Mean+/-SD) in unilateral group and 20.32+/-8.37 PD (Mean+/-SD) in bilateral group (P=0.002). Success rate was 73.6% in bilateral group, better than 63.0% in unilateral group although there was no statistically significant difference (p>0.05). CONCLUSIONS: The undercorrection rate of bilateral lateral rectus recession is less than that of unilateral lateral rectus recession and more satisfactory surgical outcome was obtained in bilateral lateral rectus recession; therefore bilateral lateral rectus recession can lead to good result in 20~25 PD intermittent exotropia for basic type.