Validity of visual acuity screening by elementary school teachers

Abstract

Conceptual Background: The management and detection of refractive errors in childhood is now multidisciplinary, where screening programs include school staff, pediatricians, ophthalmologists and optometrists, in order to correct and prevent amblyopia. Objective: Evaluate the screening conducted by teachers trained in the assessment of visual acuity of elementary school students. Methods: A concordance study was conducted with a universe consisting of 33 teachers working in the elementary schools of: Republic of Nicaragua School, Kingdom of the Netherlands school and Republic of Paraguay School, all of which are part of the public sector schools of the Central District of Honduras. The study took place during the 2015 school year between the months of May and July. A total of 840 enrolled students from first through sixth grade were evaluated. The measurement of visual acuity was performed using a Snellen chart by both teachers and residency doctors taking as cutoff any measurement under 20/30 in the better eye. The evaluation done by the residents was considered the gold standard used to determine the sensitivity and specificity of the measurements performed by the teachers. Results: the sensitivity and specificity of screening performed by teachers were 100% and 74.07% respectively, with positive predictive value of 65% and negative predictive value of 100%. The result of Cohen’s Kappa index was of 0.65. Conclusions: The results of this study suggest that visual acuity screening executed by teachers shows acceptable validity to identify positive cases of visual acuity loss and that it is best to choose a highly sensitive test if the objective is to obtain more false positives than false negatives.