Strabismus might be a risk factor for amblyopia recurrence

Abstract

Previous reports have suggested that one-fourth of amblyopic subjects present with recurrence of amblyopia even after successful primary treatment. Risk factors for amblyopia recurrence are insufficiently studied, but therapy weaning has recently been suggested as a method for reducing the risk of recurrence. In the second phase of a prospective study examining the results of treatment for amblyopia, all 35 children with successful primary amblyopia treatment were put on maintenance therapy. Maintenance therapy consisted of low-intensity patching, atropine, or blurring filter, and all children were regularly examined up to at least 8 years of age. Mean age at start of maintenance therapy was 4.3 years (range, 2-7 years). Of the 35 cases with successful primary treatment, 6 cases deteriorated >or=0.2 logMAR, which was considered recurrence of amblyopia. Two of these cases had a second recurrence. Notably, all six subjects presenting with recurrence had microstrabismus. This finding was just outside statistical significance at the 95% confidence level (p = 0.06), but the sample size was small. All but one of the recurrences appeared within 6 months after successful primary treatment. Age at successful primary treatment or initial interocular difference of visual acuity did not affect the risk of recurrence. Recurrence of amblyopia occurred in 17% of patients despite maintenance therapy and was associated with microstrabismus. The majority of recurrences occurred within the first 6 months after primary treatment.