Intermittent exotropia: comparison of treatments.

PURPOSE: To identify the best treatment option for intermittent exotropia.

METHODS: A retrospective analysis of the progress of 150 treated intermittent exotropia patients was performed. Treatment forms considered are: (i) surgery combined with orthoptic/occlusion therapy; (ii) surgery; (iii) orthoptic/occlusion therapy; and (iv) observation. Pearson's chi(2)-analysis of association of therapy form with success was performed. Reduction of exodeviation in prism dioptres between groups and subgroups were compared at 6 months, 1, 2 and 5 years follow up and the "within group" variations were compared. Exodeviation reduction in prism dioptres per millimetre of horizontal rectus surgery performed in the "surgery with orthoptic/occlusion therapy" and "surgery only" groups were compared.

RESULTS: Chi(2)-analysis revealed a significantly highest (P < 0.001) association with success in the "surgery with orthoptic/occlusion therapy" group at follow up. ANOVA analysis revealed that surgery with orthoptic/occlusion therapy resulted significantly (P < 0.001) in the highest reduction of exodeviation as compared with the other three treatment modalities at each follow up. Reduction of exodeviation in prism dioptres per millimetre of horizontal rectus surgery performed was significantly higher (P < 0.05) in the surgery with orthoptic/occlusion therapy group as compared with surgery only at all follow ups. Chi(2)-test revealed no significant association of success with the magnitude of initial exodeviation (P > 0.05).

CONCLUSION: Surgery with preoperative orthoptic/occlusion therapy had the highest success rates. Surgery with orthoptic/occlusion therapy was more effective in reducing exodeviation (prism dioptres per millimetre of horizontal rectus surgery), compared with surgery only.