Visual Acuity Screening By by School Teachers in Far West Nepal: A randomized trial of alternate screening models

Background Studies have not examined alternate school visual acuity screening methods in Nepal in terms of accuracy and cost. Objective To validate recent evidence from India of the effectiveness and cost of alternate school visual acuity screening models involving all class teachers (ACTs) versus a few selected teachers (STs). Method This was a prospective cluster randomized controlled study. The sample size was 5000 students. Five schools were randomly selected for the all-class teachers or intervention arm and four schools for selected teachers or standard arm. Teachers from both arms were trained to identify children aged 6 years and above with Snellen visual acuity 6/9 or worse in either eye as well as obvious ocular abnormalities and refer them to an ophthalmic team. The screen positive and negative children as well as cost for screening were calculated in STATA software (version 11.0; StataCorp, Texas, USA). Result All class teachers (80 teachers) screened 3713 children and STs (9 teachers) screened 2064 children aged 6 to 15 years. All class teachers had better sensitivity, 95.1% (95% CI: 91.9-98.2) and specificity, 92.8% (95% CI: 92.0-93.6) compared to selected teachers: sensitivity, 73.2% (95% CI: 64.4-82.0) and specificity, 85.3% (95% CI: 83.8- 86.7). The cost of screening per child with refractive error and or other ocular abnormalities was $3.05 for all class teachers and $ 5.29 for selected teachers. Conclusion A school vision screening involving all class teachers in Nepal was more accurate than selected teachers in identifying refractive error and or other ocular abnormalities at approximately 60% of the cost.