Mi Young Choi

Comparison of Outcomes of Unilateral Lateral Rectus Recession for Exotropia between First and Second Operations

Purpose To compare the outcomes of unilateral lateral rectus recession between the first operation and second operation for exotropia. Methods Thirty-two patients who underwent unilateral lateral rectus recession for exotropia of 15 to 20 prism diopters (PD) were investigated. The follow-up period was at least 6 months. We classified 17 patients without a surgical history for exotropia (first operation group) and 15 patients with a previous procedure (second operation group). Surgical success was defined as an exodeviation or esodeviation of less than 10 PD at the primary position. Postoperative deviation angles and success rates were compared between the two groups. Results There were no significant differences in the age, gender, visual acuity (logarithm of the minimal angle of resolution), preoperative deviation, and amount of recession between the two groups. Postoperative deviations were -1.7 ± 5.5:1.3 ± 5.1 PD at one day, 4.3 ± 3.8:5.6 ± 5.1 PD at 1 month, 4.3 ± 4.3:3.0 ± 8.1 PD at 3 months, and 5.0 ± 4.3:4.5 ± 7.2 PD at 6 months post-operation, and there was no statistically significant difference between the two study groups. Surgical success rate were 95.2:100% at one day, 95.2:92.9% at 1 month, 90.5:85.7% at 3 months, and 90.0:92.9% a 6 months post-operation. Conclusions In patients with exotropia of 15 to 20 PD, no significant difference was found in terms of the postoperative deviation angle and the surgical success rate between the first operation and the second operation groups. Unilateral lateral rectus recession can lead to similar results in 15 to 20 PD exotropia for the first operation or recurrent exotropia.

Postoperative changes of intermittent exotropia type as classified by 1-hour monocular occlusion

Purpose To evaluate postoperative changes of the intermittent exotropia type as classified by 1-hour monocular occlusion test. Design Institutional, retrospective study. Methods We retrospectively reviewed the medical records of 179 patients who had undergone surgery for intermittent exotropia with a postoperative follow-up of 6 months or more. We evaluated the exodeviation obtained before and after 1-hour monocular occlusion preoperatively and again at postoperative 1, 3 and 6 months. Intermittent exotropia was divided into 4 types according to Burian’s classification. The main outcome measure was the distribution of intermittent exotropia type based on 1-hour monocular occlusion in both pre- and postoperative periods. Results Of the 179 patients, 152 (84.9%) were assigned preoperatively to the basic type, 14 (7.8%) to the pseudo-divergence excess type, and 13 (7.8%) to the convergence insufficiency type. At postoperative 1, 3, and 6 months, the exotropia-type distribution was shifted predominantly to the basic type (p<0.001, p = 0.004, p = 0.029, respectively). Among the preoperative basic-type patients, 96.9% maintained that type postoperatively. However, only 18.2 and 11.1% of the pseudo-divergence excess and convergence insufficiency types maintained the same type. The proportions of the basic type had increased at postoperative 6 months, from 87.8 to 95.7% for bilateral lateral rectus (BLR) recession, from 73.7 to 92.3% for unilateral recess-resect (R&R), and from 88.0 to 95.0% for unilateral lateral rectus (ULR) recession. Conclusion The type of intermittent exotropia changed mostly to the basic type postoperatively even as classified after 1-hour monocular occlusion. This finding was consistent regardless of the surgical methods (BLR, ULR recession and R&R).

Effect of combining inferior oblique muscle weakening procedures with exotropia surgery on the surgical correction of exotropia

Purpose To determine whether the inferior oblique (IO) muscle weakening procedure combined with exotropia surgery affects the surgical correction of exotropia. Design Institutional, retrospective study. Methods We retrospectively reviewed the medical records of 310 patients who had undergone exotropia-correcting surgery combined with IO weakening (group A, 64 patients) or without IO weakening (group B, 246) with a postoperative follow-up of 6 months or more. The main outcome measures were the postoperative mean angle of horizontal deviation, the success rate, and the overcorrection rate. Surgical success was defined as an alignment between 10 prism diopters (PD) of exodeviation and 5 PD of esodeviation. Results The postoperative mean angles of exodeviation, throughout the follow-up period, did not significantly differ between the groups. Although the surgical success rate was higher in group B at postoperative 1 month (p = 0.035), there was no statistical difference between the 2 groups from postoperative 6 months.: The final success rates were 56.3 and 51.6% (p = 0.509). The overcorrection rate was significantly higher in group A at postoperative 1, 6 and 24 months (p = 0.017, p = 0.028, p = 0.030, respectively); however, at the final follow-up, there was no overcorrection in either group. Conclusion The overcorrection rate was higher in group A until postoperative 2 years, even though the mean angles of exodeviation and the success rates did not significantly differ between the 2 groups. Surgeons should be mindful of overcorrection when planning exotropia surgery combined with the IO weakening procedure.