Electronically measured compliance with occlusion therapy for amblyopia is related to visual acuity increase

Purpose: We set out to determine whether the children who have low compliance (measured electronically) with occlusion therapy for amblyopia are those with insufficient increase of visual acuity. Methods: In 14 newly identified amblyopic children (mean age 4.3+/-1.9 years), compliance was measured electronically over a period of I week, 6 months after the start of occlusion therapy. Compliance was measured with an Occlusion Dose Monitor (ODM). The measurements took place during planned domiciliary visits. The children were diagnosed with anisometropia (n=5), strabismus (n=4) and anisometropia and strabismus (n=5). Compliance was expressed in percentages of the electronically registered time compared with the prescribed occlusion time. Satisfactory acuity increase following 6 months of occlusion therapy was defined on reaching any of the following criteria: acuity increase expressed as a ratio between acuity of the amblyopic eye and acuity of the good eye of more than 0.75, acuity of the amblyopic eye exceeding 0.5 as measured on the E-Chart or Landolt-C, or three LogMAR lines of increase in acuity. Results: Measured compliance averaged 80% in the eight children who had a satisfactory acuity increase and 34% in the six children who had an unsatisfactory visual acuity increase. Children with low acuity increase had statistically significantly lower compliance (P=0.038). Conclusion: The general assumption among orthoptists, that compliance with occlusion therapy for amblyopia is low in children with insufficient acuity increase, has been validated by electronic, objective means.