Type of the recurrent exotropia after bilateral rectus recession for intermittent exotropia

Surgical outcomes of unilateral lateral rectus recession versus recess-resect in children with convergence insufficiency type intermittent exotropia

To determine the efficacy of unilateral lateral rectus recession (ULR) for convergence insufficiency-type intermittent exotropia (CI-type IXT), we compared surgical outcomes following ULR and recess‒resect (RR) procedures for CI-type IXT. In this retrospective study, medical records of 57 children who underwent ULR (n = 30) or RR (n = 27) for CI-type IXT of less than 25 PD at distance with a postoperative follow-up of 6 months or more were reviewed. Surgical success was defined as an alignment between 10 PD exodeviation and 5 PD esodeviation at distance and near fixation. The postoperative exodeviation showed no significant difference between the two groups at the last follow-up. A significant reduction in the mean near-distance difference was achieved postoperatively in both groups: from 5.4 PD preoperatively to 2.5 at last follow-up after ULR, and from 8.2 to 2.4 after RR (both p = 0.001). However, this difference between ULR and RR was not statistically significant (p > 0.05). The success rate at the last follow-up was 63.3% for ULR and 70.4% for RR (p = 0.574). ULR was found to be an effective treatment for CI-type IXT, with similar surgical outcomes to RR.

Surgical Outcomes of Patients with Diagnostic Preoperative Monocular Occlusion in Intermittent Exotropia

We evaluated surgical outcomes of bilateral rectus (BLR) recession in patients with intermittent exotropia who underwent diagnostic monocular occlusion. Records of patients with intermittent exotropia who were preoperatively examined one-hour monocular occlusion and underwent BLR recession were reviewed retrospectively. Patients were classified into two groups based on change in exodeviation angle: responders (≥5 change in prism diopters [PD] after occlusion) or non-responders (<5 PD change after occlusion). BLR recession amount was determined by maximal angle deviation after occlusion tests in both groups. Overall follow-up period was 38.81 ± 24.09 months for non-responders (n = 106) and 38.52 ± 19.87 months for responders (n = 142) (p = 0.766). There was no difference in deviation before monocular occlusion between the two groups. Mean angle of deviation at distance (24.23 ± 6.27 PD) and near fixation (25.46 ± 6.78 PD) increased to distance (29.95 ± 6.43 PD) and near deviation (32.15 ± 6.17 PD) after occlusion in the responder group. At postoperative 1 year, surgical success rate was higher in responders (71.1%) than in non-responders (52.8%) (p = 0.003). Kaplan-Meier survival analysis revealed significantly higher surgical success in responders (p = 0.001, log-rank test). Preoperative diagnostic monocular occlusion in patients with intermittent exotropia can influence surgical outcomes by identifying the latent exodeviation angle.

Bilateral Lateral Rectus Recession for the Treatment of Recurrent Exotropia after Bilateral Medial Rectus Resection

PURPOSE

To evaluate the efficacy of bilateral lateral rectus muscle recession (BLR) to treat recurrent exotropia after bilateral medial rectus muscle resection (BMR).

METHODS

Twenty-four patients who underwent BLR for recurrent exotropia and were followed up for more than 6 months were included in this retrospective study. All of them had prior BMR. The angle of deviation, success rates, near stereopsis, and surgical effect of BLR were evaluated. Surgical success was defined as postoperative deviations ≤10 prism diopters (PD).

RESULTS

The overall mean follow-up time after reoperation for patients was 24.13 ± 15.01 months (range 6-60 months). The mean angle of deviation at distance was significantly reduced from -37.75 ± 14.93 PD to +1.50 ± 6.43 PD (p < 0.001). Twenty-two (91.6%) of 24 patients had successful outcomes, 1 (4.2%) had overcorrection, and 1 (4.2%) had undercorrection at the last follow-up. Improved stereopsis after reoperation was observed in 78.3% (18/23) of the patients. The mean surgical effect was 2.78 ± 0.71 PD/mm.

CONCLUSION

Based on our results, BLR could be an effective and safe method for treating recurrent exotropia after a moderate to large amount of BMR.

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).