Applicability of the Smart Vision Screening Instrument among Chinese Primary School Students

Abstract

Background: A smart vision screening instrument was applied for screening low eyesight in primary school students in Wuhan, China. We aimed to compare the differences in test results between this instrument and lamp-box visual acuity charts, assess the validity of the screening results, and perform a preliminary comparison of the cost inputs of the two approaches.

Methods: In this cross-sectional study conducted in Wuhan, China in 2017, vision tests were performed on the same day among enrolled primary school students by using the two approaches. The t-test and kappa test were performed to compare the differences, and the indicators of validity were calculated and receiver operating characteristic (ROC) curves were drawn. Existing cost-input data were collected and the budget was analyzed.

Results: In total, 1001 schoolchildren were included, and the prevalence of low eyesight was 21.18% (95% CI: 18.71-23.87%). The test results of the two approaches were not statistically different (t=1.929, P>0.05) and showed moderate consistency (kappa=0.519, P<0.001). Sensitivity and specificity of the instrument were 84.90% (95% CI: 79.21-89.30%) and 91.63% (95% CI: 89.42-91.64%), respectively; positive predictive value was 73.17% (95% CI: 67.10-78.51%); and negative predictive value was 95.76% (95% CI: 94.00-97.04%). Area under the ROC curve was 0.883 (95% CI: 0.853-0.913) and significantly differed from 0.5 (P<0.001). The budget when using the instrument decreased 48.07% compared to that when using lamp-box visual acuity charts.

Conclusion: The test result of the instrument is reliable, and using it to conduct screening is cost-saving. Therefore, it might be popularized for vision monitoring in schoolchildren.