Amblyopia treatment outcomes after screening before or at age 3 years: follow up from randomised trial

Abstract Objective: To assess the effectiveness of early treatment for amblyopia in children. Design: Follow up of outcomes of treatment for amblyopia in a randomised controlled trial comparing intensive orthoptic screening at 8, 12, 18, 25, 31, and 37 months (intensive group) with orthoptic screening at 37 months only (control group). Setting: Avon, southwest England. Participants: 3490 children who were part of a birth cohort study. Main outcome measures: Prevalence of amblyopia and visual acuity of the worse seeing eye at 7.5 years of age. Results: Amblyopia at 7.5 years was less prevalent in the intensive group than in the control group (0.6% v 1.8%; P=0.02). Mean visual acuities in the worse seeing eye were better for children who had been treated for amblyopia in the intensive group than for similar children in the control group (0.15 v 0.26 LogMAR units; P<0.001). A higher proportion of the children who were treated for amblyopia had been seen in a hospital eye clinic before 3 years of age in the intensive group than in the control group (48% v 13%; P=0.0002). Conclusions: The intensive screening protocol was associated with better acuity in the amblyopic eye and a lower prevalence of amblyopia at 7.5 years of age, in comparison with screening at 37 months only. These data support the hypothesis that early treatment for amblyopia leads to a better outcome than later treatment and may act as a stimulus for research into feasible screening programmes. What is already known on this topic Observational studies have produced conflicting results about whether early treatment for amblyopia gives better results than later treatment A recent systematic review highlighted the lack of high quality data available and recommended the cessation of preschool vision screening programmes This has led to fierce debate and to confusion about the provision of vision screening services What this study adds Children treated for amblyopia are four times more likely to remain amblyopic if they were screened at 37 months only than if they were screened repeatedly between 8 and 37 months Children screened early can see an average of one line more with their amblyopic eye after treatment than children screened at 37 months Early treatment is more effective than later treatment for amblyopia, supporting the principle of preschool vision screening

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