Linear regression model of potential predictors of final uncorrected LogMAR visual acuity
| Variables | Model adjusted only for baseline visual acuity (n= 910) | Full model* (n=910) | ||
| Regression coefficient†‡ (95% CI) | P value | Regression coefficient‡ (95% CI) | P value | |
| Baseline uncorrected visual acuity (LogMAR) | 0.335 (0.284 to 0.386) | <0.001 | 0.414 (0.340 to 0.487) | <0.001 |
| Intervention group | 0.034 (−0.012 to 0.080) | 0.142 | 0.045 (0.006 to 0.084) | 0.027 |
| Age | −0.001 (−0.012 to 0.010) | 0.839 | ||
| Male gender | 0.022 (0.003 to 0.041) | 0.025 | 0.023 (0.003 to 0.043) | 0.026 |
| Only child in family | −0.045 (−0.099 to 0.009) | 0.097 | −0.041 (−0.091 to 0.009) | 0.102 |
| Believes wearing eyeglasses harms vision | −0.003 (−0.028 to 0.021) | 0.776 | ||
| Baseline eyeglasses ownership† | −0.054 (−0.079 to −0.028) | <0.001 | −0.042 (−0.067 to −0.016) | 0.002 |
| VA <6/18 both eyes | −0.005 (−0.049 to 0.039) | 0.824 | ||
| Both parents migrant out | 0.014 (−0.020 to 0.049) | 0.41 | ||
| Total time spent on phone (hours/day) | 0.001 (−0.010 to 0.012) | 0.869 | ||
| Total time spent on computer (hours/day) | 0.015 (0.001 to 0.029) | 0.037 | 0.012 (−0.002 to 0.027) | 0.083 |
| Rural residence | −0.005 (−0.059 to 0.049) | 0.843 | ||
| At least one parent with ≥9 years of education | 0.015 (−0.031 to 0.061) | 0.512 | ||
| Boarding at school | −0.014 (−0.044 to 0.016) | 0.35 | ||
| At least one family member wearing eyeglasses | −0.005 (−0.025 to 0.014) | 0.572 | ||
| Mean (SD) refractive error (dioptres) (−0.5 to 0.5 D as reference) | ||||
| ≤−2 | −0.093 (−0.166 to −0.021) | 0.013 | −0.083 (−0.155 to −0.011) | 0.025 |
| −2 to −0.5 | −0.041 (−0.098 to 0.016) | 0.155 | −0.040 (−0.098 to 0.019) | 0.178 |
| ≥0.5 | 0.060 (−0.051 to 0.171) | 0.28 | ||
| Blackboard use (less than half as reference) | ||||
| Half of teaching | −0.044 (−0.082 to −0.006) | 0.024 | −0.048 (−0.083 to −0.013) | 0.009 |
| >Half of teaching | 0.007 (−0.050 to 0.066) | 0.787 | ||
*Including variables associated with visual acuity p≤0.20 in the model only adjusted for baseline visual acuity.
†Except for the regression coefficient for baseline visual acuity (simple regression), coefficients for the different variables are for multivariate regression models with endline visual acuity as dependent variable, adjusted for baseline visual acuity.
‡A negative regression coefficient indicates an association with worse endline visual acuity.
LogMAR, logarithm of the minimum angle of resolution; VA, visual acuity.