PURPOSE:Noncompliance is one of the limiting factors in the success of occlusion therapy for amblyopia. Electronic monitoring was used to investigate predictors of noncompliance, and, in a prospective randomized clinical trial, determined the effectiveness of an educational program. METHODS:Compliance was measured electronically during 1 week every 3 months in 310 newly diagnosed amblyopic children. The family's demographic parameters and the child's clinical parameters were assessed for their influence on the level of compliance. In addition to standard orthoptic care, children were randomized to receive an educational cartoon story, reward stickers, and an information sheet for the parents (intervention group), or a picture to color (reference group). These and the electronic device were distributed during home visits by researchers. The primary outcome measure was the percentage of compliance (actual/prescribed occlusion time) in the two groups. The secondary outcome measure was the influence of demographic and clinical factors on compliance. RESULTS:Compliance was associated with parental fluency in the national language, country of origin, level of education, and initial visual acuity of the child. During the first 1-week measurement period children in the intervention group had better compliance than the reference group had (78% +/- 32% vs. 57% +/- 40%; P < 0.0001), and fewer children were not occluded at all (3 vs. 23 in the reference group; P < 0.0001). This difference remained throughout the study period. CONCLUSIONS:Poor parental fluency in the national language, a low level of education, and poor acuity at the start of treatment were predictors of low compliance. An educational program primarily aimed at the child improved compliance and reduced the number of children who did not comply with occlusion at all.