The Effect of Alternate Occlusion on Controlling Intermittent Exotropia in Children

The aim of the study was to investigate the effect of alternate occlusion on controlling intermittent exotropia in children between 3 and 8 years.
In this interventional before-after study, the ability of 28 children to control deviation at far and near was evaluated based on an office control scale, routinely used in eye clinics and the Holmes scale. Stereopsis and fusion were assessed using the Titmus and Worth 4-dot test in each assessment session, respectively. Patch therapy was used for children based on eye dominancy. Two-hour alternate daily occlusion was prescribed for children with no dominancy. For children with dominancy, 2-hour occlusion of the dominant eye for 5 days and the non-dominant eye for 2 days for up to 3 months in three consecutive 3-month periods was introduced. All measurements were repeated at 3 different times (3, 6, and 9 months) after treatment.
For all children with mean ages of 4.7±1.56 years, deviation controlling at far, improved significantly after 3 months of treatment by two scales, in comparison to the before of study(p=0.005 for the office control and p˂0.001 for Holmes score). Also there was an improvement in far deviation controlling in 6 and 9 months after treatment in comparison to the before of treatment (p=0.008 for the office control after 6 and 9 month and p˂0.001 after 6 and p=0.010 after 9 month for Holmes score). However there were no significant differences between the results of the 3 months and 6 months after treatment with each other, the 3 months and 9 months with each other and 6 months and 9 months with each other. Deviation controlling at near showed significant improvement in all three periods of treatment based on Holmes criteria in comparison to the before of study (p=0.007 for 3 months, p=0.004 for 6 months and p=0.014 for 9 months).
The near stereopsis was better at 9 months of treatment in comparison to the before of study (p=0.028) and 9 months after treatment compared to the 3 months of treatment, significantly improved (P = 0.043). Comparing 6 months rather than before treatment it was a sign of improved stereopsis; however, this improvement was not statistically significant (p=0.068) while there was no improvement in other courses. Measurements of fusion with Worth4-dot test did not show significant progress between all the periods.
The alternate occlusion is significantly effective in controlling intermittent exotropia. As a result, it can be used as a useful method in order to postpone the surgery or even eliminate the need for surgery in patients with intermittent exotropia.