Continued care and provision of glasses are necessary to improve visual and academic outcomes in children: Experience from a cluster-randomized controlled trial of school-based vision screening.

Objective: To assess the effectiveness of a kindergarten vision screening program by randomly assigning schools to receive or not receive vision screening, then following up 1.5 years later.

Methods: Fifty high-needs elementary schools were randomly assigned to participate or not in a vision screening program for children in senior kindergarten (SK; age 5‒6 years). When the children were in Grade 2 (age 6‒7 years), vision screening was conducted at all 50 schools.

Results: Contrary to expectations, screened and non-screened schools did not differ in the prevalence of suspected amblyopia in Grade 2 (8.6% vs. 7.5%, p = 0.10), nor prevalence of other visual problems such as astigmatism (45.1% vs. 47.1%, p = 0.51). There was also no difference between screened and non-screened schools in academic outcomes such as the proportion of children below grade level in reading (33% vs. 29%) or math (44% vs. 38%) (p = 0.86). However, more children were wearing glasses in screened than in non-screened schools (10.2% vs. 7.8%, p = 0.05), and more children reported their glasses as missing or broken (8.3% vs. 4.7%, p = 0.01), suggesting that SK screening had identified successfully those in need of glasses. Examination of individual results revealed that 72% of children diagnosed and treated for amblyopia in SK no longer had amblyopia in Grade 2.

Conclusion: The prevalence of amblyopia and other visual problems was not reduced in Grade 2 by our SK vision screening program, perhaps because of poor treatment compliance and high attrition. The results suggest that a single screening intervention is insufficient to reduce visual problems among young children. However, the data from individuals with amblyopia suggest that continuing vision care and access to glasses benefits children, especially children from lower socioeconomic class.