The Effect of Preoperative Occlusion Therapy on Long-term Outcome after Surgery for Early-onset Exotropia

PURPOSE: To investigate the effect of preoperative part-time occlusion therapy on long-term surgical success in early-onset exotropia. METHODS: The medical records of patients who underwent surgery for exotropia with onset before the first year of age and who were followed for ≥3 years were reviewed. Patients were divided into two groups according to the degree of compliance with part-time occlusion therapy: the good compliance group (>50% adherence rate) and the poor compliance group (≤50% adherence rate). Surgical success was defined as orthophoria to exodeviation less than 10 prism diopters both at distance and near. The level of postoperative stereopsis was compared between the two study groups among total enrolled patients and among those with constant exotropia. RESULTS: Of the 51 patients, 26 were assigned to the good compliance group and the remaining 25 patients to the poor compliance group. The surgical success rate was significantly higher in the good compliance group than in the poor compliance group (80.8% vs. 52.0%, p = 0.040). Among 24 constant exotropia patients (12 patients for each group), the success rate was insignificantly higher in the good compliance group than in the poor compliance group (75.0% vs. 58.3%, p = 0.448). The good compliance group had a better level of stereopsis than the poor compliance group (p = 0.045 for all 44 patients, p = 0.020 for 19 patients with constant exotropia). CONCLUSIONS: Preoperative part-time occlusion therapy was useful for improving the surgical outcome of early-onset exotropia and postoperative stereopsis.

The Effects of Part-Time Occlusion Therapy Shortened to One or Two Hours in Intermittent Exotropia

PURPOSE: To evaluate the compliance level of therapy and the change in exo-angle after 1 or 2 hours of part-time occlusion therapy in intermittent exotropia. METHODS: This retrospective study included 97 patients with intermittent exotropia who were followed-up for more than 6 months after their initial visit. We evaluated the exo-angle and prescribed either 1 hour or 2 hours of part-time occlusion therapy for the fixating eye. After 6 months, the exo-angle was reevaluated and compliance was examined. Patients were divided into 2 groups according to the occlusion therapy time: the 1-hour patching group (33 patients) and the 2-hour patching group (64 patients). Compliance and deviation angle were retrospectively reviewed and compared between the 2 groups. We evaluated the exo-angle of patients with compliance over 50% (1-hour patching group (31 patients), 2-hour patching group (51 patients)). RESULTS: The mean exo-angles on the first visit were 22.61 +/- 5.78 PD (prism diopters) at distance and 22.88 +/- 8.11 PD at close-range in the 1-hour patching group, and 26.17 +/- 4.55 PD at distance and 25.27 +/- 8.54 PD at close-range in the 2-hour patching group. The proportion of patients with compliance over 50% was higher in the 1-hour patching group (93.94%) than in the 2-hour patching group (79.69%, p = 0.013). There were significant decreases in distant and close- range deviation angles after part-time occlusion in patients with compliance over 50% in both groups (1-hour patching group distant p = 0.042, close-range p = 0.002; 2-hour patching group distant p < 0.001, close-range p < 0.001). The magnitude of deviation angle decrease was not statistically significant between the 2 groups (ANCOVA; distant p = 0.461, near p = 0.761). CONCLUSIONS: One or 2 hours of part-time occlusion therapy in intermittent exotropia provided beneficial effects, including decreasing the deviation angle. The magnitude of deviation angle decrease, however, was not different between the 2 times of therapy. Compliance was higher in the 1-hour part-time occlusion therapy group. Therefore, 1-hour part-time occlusion therapy could be effective in patients with poor cooperation.

The Long-Term Effect of Part-Time Occlusion Therapy According to Compliance in Recurrent Intermittent Exotropia

PURPOSE: To evaluate the reoperation rate and the change of exo-angle according to compliance level of part time occlusion therapy in recurrent intermittent exotropia. METHODS: This retrospective study included 52 patients of recurrent intermittent exotropia who followed up more than 5 years after their first operation. They were ordered part time occlusion therapy for recurrent exotropia. The patients were divided into 4 groups according to the level of compliance of part time occlusion therapy ('excellent', 'good', 'fair', 'poor'). We evaluated the reoperation rate in 5 years after the first operation and the change of exo-angle from the early recurrent time according to compliance levels. RESULTS: The reoperation rate within 5 years after the first operation of 'excellent' and 'good' compliance groups was lower than that of 'fair' and 'poor' groups (33.3, 26.3, 73.7 and 45.5% respectively) and the degree of exo-angle progression from the early recurrent time of the 'excellent' and 'good' compliance groups was less than that of 'fair' and 'poor' compliance groups, both results of which were statistically significant (p=0.02, 0.03). CONCLUSIONS: Part time occlusion therapy in recurrent intermittent exotropia has good long-term effects of decreasingreoperation rates in patients with a high level of compliance.

Deterioration of Accommodative Esotropia during Part-time Occlusion Therapy

The authors report two cases of suddenly deteriorated accommodative esotropia with amblyopia during part-time occlusion therapy. A 7-year-old girl with right accommodative esotropia, which was well controlled, showed marked increase in esodeviation after part-time occlusion and regained orthophoria without occlusion. This phenomenon was repeated. Recession of both medial recti was performed and orthophoria was well maintained at both distant and near targets. Accommodative esotropia of a 9-year-old boy with glasses also showed a striking increase in esodeviation after part-time occlusion. The authors recommended wearing only glasses without occlusion or surgery and he recovered fusion. Three months later, orthophoria was maintained at distant target, with 8PD esophoria at near target with glasses. Although this complication should be considered before occlusion therapy, it must be taken continuously if needed, because an increase of the deviation size with occlusion may simply reflect a true deviation and may not be a poor prognostic sign.