Abstract
Purpose: :
To use objective compliance and visual outcome measures to compare five different patching strategies for treating amblyopia with the aim of establishing an optimal patching regime for amblyopia treatment. One of the strategies involved administering an educational program.
Methods: :
153 amblyopes (49 anisometropic, 51 strabismic, 53 mixed) were randomised into one of five patching regimes designed to progressively increase the amount of daily patching: (i) 0-hours (control group, n=29), (ii) 3-hours (n=30), (iii) 6-hours (n=32), (iv) 10-hours (n=31) and (v) 10-hours after receiving an educational program (n=31). Compliance was measured using occlusion dose monitors for the entire patching period of 12 weeks after a 6-week period of refractive adaptation. Visual acuity was monitored every three weeks using LogMAR crowded Glasgow Acuity Cards.
Results: :
Median compliance was better for higher patching dosages (69.2% and 73.4% for 10-hour educational intervention and non-intervention group, respectively) compared to lower patching dosages (44.3% and 53.1% for 6-hour and 3-hour groups, respectively). More drop-outs were associated with higher patching dosages, however the educational intervention reduced the proportion of drops-outs and poor compliers by more than half in the 10-hours patching groups (p=0.019). Visual outcomes progressively improved from the 0-hours group through to the 10-hours group with educational intervention. There was clear dose-response between absolute patching times recorded and visual improvement for the strabismic and mixed groups with no plateau effect at higher dosages (p<<0.0001). There was no correlation between absolute patching times recorded and visual improvement for anisometropes.
Conclusions: :
These findings advocate the use of a high intensity patching regime for strabismus and mixed amblyopes supplemented using an educational intervention. This mode of treatment is likely to substantially reduce treatment times resulting in less psychological trauma to children, easier administering of patching by parents and reduced costs to health services. The study also highlights that anisometropia and strabismus respond differently to occlusion therapy possibly because they represent different diseases. The best mode of treatment for anisometropia has yet to be determined.
Clinical Trial: :
www.ISRCTN.org ISRCTN05346737
Keywords: amblyopia • visual development: infancy and childhood • neuro-ophthalmology: cortical function/rehabilitation