Table 6.
Multivariate regression of the interactive effect of smartphone and tablet usage (<2 h per day vs. ≥2 h per day) on 1-year change in spherical equivalent refraction (SER), imputed data.
| Smartphone Usage (h/day) | Tablet Usage (h/day) | Model 1 | Model 2 | Model 3 | ||||
|---|---|---|---|---|---|---|---|---|
| Mean (95% CI) | p-Value (Comparison with <2 Hours per Day on Both Smartphone and Tablet Usages) | Mean (95% CI) | p-Value (Comparison with 0–1) | Mean (95% CI) | p-Value (Comparison with <2 Hours per Day on Both Smartphone and Tablet Usages) | |||
| Right eye | ||||||||
| <2 | <2 | −0.10 (−0.21, −0.01) | Ref | −0.12 (−0.22, −0.01) | Ref | −0.09 (−0.24, 0.05) | Ref | |
| ≥2 | <2 | −0.27 (−0.34, −0.20) | 0.02 | −0.28 (−0.35, −0.21) | 0.02 | −0.25 (−0.38, −0.13) | 0.01 | |
| <2 | ≥2 | −0.15 (−0.35, 0.05) | 0.73 | −0.16 (−0.36, 0.05) | 0.73 | −0.13 (−0.36, 0.09) | 0.71 | |
| ≥2 | ≥2 | −0.21 (−0.32, −0.11) | 0.18 | −0.22 (−0.33, −0.11) | 0.17 | −0.20 (−0.34, −0.05) | 0.17 | |
| Left eye | ||||||||
| <2 | <2 | −0.13 (−0.23, −0.03) | Ref | −0.13 (−0.23, −0.02) | Ref | −0.15 (−0.29, −0.003) | Ref | |
| ≥2 | <2 | −0.25 (−0.32, −0.18) | 0.07 | −0.26 (−0.33, −0.18) | 0.051 | −0.28 (−0.40, −0.15) | 0.055 | |
| <2 | ≥2 | −0.22 (−0.42, −0.01) | 0.11 | −0.21 (−0.42, −0.01) | 0.45 | −0.22 (−0.44, 0.0005) | 0.52 | |
| ≥2 | ≥2 | −0.17 (−0.27, −0.06) | 0.08 | −0.17 (−0.28, −0.06) | 0.57 | −0.18 (−0.33, −0.04) | 0.64 | |
| Pillai’s trace p-value | 0.27 | 0.002 | 0.25 | |||||
Model 1 adjusted for age, sex, and baseline SER; Model 2 adjusted for age, sex, baseline SER, parents’ short-sightedness, BMI, and time spent on moderate-to-vigorous physical activity; Model 3 adjusted for age, sex, baseline SER, parents’ short-sightedness, BMI, time spent on moderate-to-vigorous physical activity, and caregiver-reported socio-economic status.