Intermittent exotropia in children is a common type of strabismus in clinical practice, and surgery is the only definitive treatment for it. However, there is still controversy regarding the timing of surgery. Some advocate early surgery and others advocate surgery in adulthood, but in either case, bilateral visual impairment is currently one of the more consistent indicators of a reasonable choice of surgical treatment. Recently, Cotter et al. investigated the efficacy of intermittent masking versus observation alone in children with intermittent exotropia. The multicenter, randomized clinical trial included 358 untreated (except refractive correction) children with intermittent exotropia aged 3-10 years, with near stereopsis of 400″ or better in both eyes, randomized to an observation group (no treatment for 6 months) and a masking group (masking for 3 hours per day for 5 months, with no masking in month 6, a de-masking washout period). The main outcome observed was whether the condition worsened (constant exotropia or near stereopsis decreased by more than 2 octaves). The results found that children who were covered for 3 hours per day progressed less than children who were observed alone, although the rate of disease progression was not high in either group. 324 children (91%) completed the study, with 10 of 165 children in the observation group (6.1%) progressing in disease and 1 of 159 children in the coverage group (0.6%) progressing. Therefore, the authors concluded that in children aged 3-10 years, the likelihood of progression of intermittent exotropia within 6 months with or without masking is small and that both approaches are reasonable in this age group.