Table 2.
Univariate association between smartphone and tablet usage (hours per day) on spherical equivalent refraction (SER, D).
| Smartphone | Usage (h/day) | Baseline | 1-Year Follow-Up | Change |
|---|---|---|---|---|
| Right eye | ||||
| 0–1 | −1.21 (2.10) | −1.38 (2.06) | −0.17 (1.17) | |
| 1–2 | −1.55 (2.00) | −1.73 (1.94) | −0.17 (1.07) | |
| 2–3 | −1.75 (2.29) | −2.05 (2.41) | −0.30 (0.70) | |
| 3–4 | −1.78 (2.27) | −1.97 (2.46) | −0.19 (0.98) | |
| 4+ | −1.87 (2.10) | −2.09 (2.18) | −0.22 (0.98) | |
| p-value | <0.001 | <0.001 | 0.72 | |
| Left eye | ||||
| 0–1 | −1.16 (2.06) | −1.38 (2.04) | −0.22 (1.20) | |
| 1–2 | −1.56 (1.97) | −1.75 (2.03) | −0.19 (1.04) | |
| 2–3 | −1.76 (2.24) | −2.02 (2.36) | −0.26 (0.70) | |
| 3–4 | −1.63 (2.28) | −1.88 (2.28) | −0.25 (0.84) | |
| 4+ | −1.81 (2.10) | −1.99 (2.19) | −0.18 (0.99) | |
| p-value | <0.001 | 0.001 | 0.84 | |
| Tablet | Usage (h/day) | Baseline | 1-Year Follow-Up | Change |
| Right eye | ||||
| 0–1 | −1.72 (2.18) | −1.96 (2.27) | −0.24 (1.01) | |
| 1–2 | −1.53 (2.00) | −1.62 (1.88) | −0.09 (1.14) | |
| 2–3 | −2.06 (2.39) | −2.30 (2.48) | −0.24 (0.90) | |
| 3–4 | −1.33 (2.06) | −1.58 (1.95) | −0.25 (0.87) | |
| 4+ | −1.62 (1.93) | −1.78 (1.99) | −0.16 (0.96) | |
| p-value | 0.13 | 0.04 | 0.37 | |
| Left eye | ||||
| 0–1 | −1.70 (2.18) | −1.92 (2.26) | −0.23 (1.05) | |
| 1–2 | −1.42 (1.98) | −1.53 (1.88) | −0.11 (0.95) | |
| 2–3 | −1.93 (2.26) | −2.21 (2.38) | −0.27 (0.81) | |
| 3–4 | −1.28 (2.00) | −1.48 (1.87) | −0.20 (1.05) | |
| 4+ | −1.51 (1.94) | −1.66 (1.98) | −0.15 (0.92) | |
| p-value | 0.10 | 0.02 | 0.48 |