Efficiency of electronically monitored amblyopia treatment between 5 and 16 years of age: New insight into declining susceptibility of the visual system

- Benefit of amblyopia treatment quantified to determine age-related susceptibility.
- Between 5 and 16 years, treatment efficiency declined nonlinearly with increasing age.
- Age had largest impact on treatment outcome before age of 7 years.
- Data permit evaluation of patching against emerging alternative treatments.

The notion of a limited, early period of plasticity of the visual system has been challenged by more recent research demonstrating functional enhancement even into adulthood. In amblyopia (“lazy eye”) it is still unclear to what extent the reduced effect of treatment after early childhood is due to declining plasticity or lower compliance with prescribed patching. The aim of this study was to determine the dose-response relationship and treatment efficiency from acuity gain and electronically recorded patching dose rates, and to infer from these parameters on a facet of age dependence of functional plasticity related to occlusion for amblyopia. The Occlusion Dose Monitor was used to record occlusion in 27 participants with previously untreated strabismic and/or anisometropic amblyopia aged between 5.4 and 15.8 (mean 9.2) years during 4 months of conventional treatment. Group data showed improvement of acuity throughout the age span, but significantly more in patients younger than 7 years despite comparable patching dosages. Treatment efficiency declined with age, with the most pronounced effects before the age of 7 years. Thus, electronic recording allowed this first quantitative insight into occlusion treatment spanning the age range from within to beyond the conventional age for patching. Though demonstrating improvement in over 7 year old patients, it confirmed the importance of early detection and treatment of amblyopia. Treatment efficiency is presented as a tool extending insight into age-dependent functional plasticity of the visual system, and providing a basis for comparisons of effects of patching vs. emerging alternative treatment approaches for amblyopia.