Visual acuity screening by school teachers in Far West Nepal: A randomized trial of alternate screening models.

Abstract

Background: School vision screening programs are more effective and less costly in comparison to primary eye care model. However, studies have not examined alternate school visual acuity screening methods in Nepal in terms of accuracy and cost. This study was conducted 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) from schools in Far West Nepal. Methods: Nine schools in Far West Nepal were randomly selected for the ACTs which is the intervention arm or STs which is the standard arm. Teachers from both arms were trained to identify children aged 6 years and above with visual acuity 6/9 or worse in either eye as well as obvious ocular abnormalities and refer them to an ophthalmic team from Geta Eye Hospital who visited the schools to examine all children regardless of initial screening. Mean values were compared using student t and Wilcoxon rank sum tests, and proportions were compared between study groups using chi square statistics. Results: A total of 3793 children in 5 ACTs schools and 2144 children in 4 STs schools were included. ACTs (80 teachers) screened 3713 children and STs (9 teachers) screened 2064 children aged 6 to 15 years. ACTs had better sensitivity (95.1% [95% CI: 91.9- 98.2]) and specificity (92.8% [95% CI: 92.0%-93.6%]) compared to STs: sensitivity (73.2% [95% CI: 64.4- 82.0]) and specificity (85.3% [95% CI: 83.8-86.7]). More children from ACTs than STs reached the Geta Eye Hospital for further investigation within 3 months (n= 10/30 [33.3%] versus n= 5/18 [27.7%]) for ACTs and STs respectively but the difference was not statistically significant. The cost of screening per child with refractive error and or other ocular abnormalities was $3.05 for ACTs and $ 5.29 for STs. Conclusion: A school vision screening program involving ACTs in Nepal was more accurate than ST screening in identifying refractive error and or other ocular abnormalities at approximately 60% of the cost.