Prevalence of Visual Accommodation Defects Associated with Screen Use in Children Aged 9 to 12 Years in 2 Schools in La Paz, Bolivia

Abstract

Objective: To determine the prevalence of visual accommodation defects associated with prolonged screen use in children aged 9 to 12 years in 2 schools in La Paz, Bolivia.

Methodology: An analytical observational cross-sectional study was conducted at Desmaissieres and San Calixto Schools in La Paz, Bolivia, among children aged 9 to 12 years, during August and September 2022. A multiple-choice survey on visual habits and risk factors was administered to each student. Subsequently, visual screening was performed using the Cover test, near point of convergence, Krimsky’s rule test, Butterfly test, and Worth test.

Results: In the pre-visual screening survey, it was found that 70% of the students did not practice visual hygiene measures. 96% of them showed signs of asthenopia. The prevalence of ocular accommodation defects was as follows: 69% had alterations in accommodation flexibility, 43% had phorias, 37% had alterations in the perception of depth of objects, and 20% had alterations in the convergence point. A higher percentage of accommodation defects were observed in patients exposed to screens for more than 4 hours daily compared to those with less screen time. Specifically, flexibility of accommodation was altered in 92% vs. 61%; near and distant convergence points were altered in 42% vs. 13%; the presence of any degree of phorias was found in 58% vs. 37%; alteration in three-dimensional vision was observed in 46% vs. 34%; and difficulty in fusing objects was noted in 21% vs. 7%.

Conclusions: Prolonged screen use negatively affects visual accommodation and is associated with a higher prevalence of asthenopia. The most common accommodation defect was a lack of accommodation flexibility, followed by phorias and altered convergence points.