Comparison of the efficacy of Lea Symbol chart and Sheridan Gardiner chart for preschool vision screening

To compare the efficacy of Lea symbols (LS) chart and Sheridan Gardiner (SG) chart for vision screening among preschool children, in a semi-urban district of South India.

Vision screening was conducted among 260 preschool children aged 3-5 years in cluster sampled kindergartens using LS chart and SG chart. Pass/fail scores and time taken for visual acuity (VA) estimation were compared. VA scores and time taken were compared using unpaired t-test. Sensitivity, specificity, and positive and negative predictive values were compared between the charts.

There was a significant difference between LS and SG charts in the VA score in both the eyes (P = 0.04). LS showed 76.09% pass score and 23.90% fail score, whereas SG showed 87.65% pass score and 12.35% fail score with a cutoff value of > 0.3 log MAR. Time for screening using LS was higher, when compared to SG, both for the right eyes (P < 0.001) and the left eyes (P < 0.001). The sensitivity of the LS was 94.74% (95% confidence interval [CI]: 70.13%-81.06%) and that of SG was 52.63% (95% CI: 45.29%-59.8%). The specificity of LS was 66.67% (95% CI: 90.26%-97.30%) and SG was 83.33% (95% CI: 70.12%-91.30%).

LS chart showed better sensitivity and negative predictive value when compared to SG chart. However, SG chart showed better specificity and positive predictive value, and screening was less time-consuming. Considering the high sensitivity and negative predictive value, LS is the preferred tool, when compared to SG chart in preschool vision screening in our population.