## 3 Results  
The 27 participants were arranged by randomized crossover design for each intervention in stage 1; for personal reasons, two participants withdrew in stage 2. The participants' clinic demographic data are presented in Table 1. The age range of the participants was 10-12 years old, 40.7% of the participants were boys, and 80.19% of the participants had experienced no eye discomfort in the previous 3 months.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Variables** & & **Frequency** & **Percentage** \\ \hline Gender & & Male & 11 & 40.7 \\  & Female & 16 & 59.3 \\ Age (years) & & 10 & 9 & 33.3 \\  & 11 & 12 & 44.4 \\  & 12 & 6 & 22.2 \\ Myopia status of father & & No & 13 & 48.2 \\  & Yes & 14 & 51.8 \\ Myopia status of mother & & No & 15 & 55.6 \\  & Yes & 12 & 44.4 \\ Education of father & & \(\leq\)12 years & 11 & 40.7 \\  & \(>\)12 years & 16 & 59.3 \\ Education of mother & & \(\leq\)12 years & 9 & 33.3 \\  & \(>\)12 years & 18 & 66.7 \\ Outside activity during the previous & & & \\  & No & 3 & 11.1 \\  & Yes & 24 & 88.9 \\ \hline \hline \end{tabular}
\end{table}
Table 1: Demographic data of the participants.  
Table 2 summarizes the postinterventional changes in logMAR visual acuity. Compared with the values before the intervention, the postinterventional logMAR visual acuity was significantly different in the VT-FFR (0.63 \(\pm\) 0.36 vs. 0.56 \(\pm\) 0.32, \(p\) \(<\) 0.001) and VT-FFR-ES groups (0.60 \(\pm\) 0.34 vs. 0.46 \(\pm\) 0.28, \(p\) \(<\) 0.001). Thus, the VT-FFR-ES intervention was identified as having the best observed outcome for logMAR visual acuity (i.e., the greatest decrease in logMAR visual acuity) (Table 2). Figure 3 presents an identity plot for logMAR visual acuity in the No function group and VT-FFR-ES group after a single intervention.  
In the chronic intervention, the average spherical equivalents in the VT-FFR-ES and Control groups were \(-\)2.59 \(\pm\) 1.88 D and \(-\)2.56 \(\pm\) 1.79 D, respectively, in the pre-test, and \(-\)2.38 \(\pm\) 1.72 D and \(-\)2.66 \(\pm\) 1.91 D, respectively (_p_ \(<\) 0.001, Table 3), in the post-test. Figure 4 presents an identity plot for pre- and post-test spherical equivalent values after 4 weeks of chronic intervention.  
\begin{table}
\begin{tabular}{l c c c c} \hline \hline
**Intervention** & **Before** & **After** & **Mean Difference** & \(p\) **a** \\ \hline Control & 0.60 \(\pm\)0.33 & 0.58 \(\pm\) 0.33 & \(-\)0.02 \(\pm\) 0.08 b,c & 0.08 \\ VT & 0.62 \(\pm\) 0.36 & 0.54 \(\pm\) 0.33 & \(-\)0.07 \(\pm\) 0.43 & 0.22 \\ VT-FFR & 0.63 \(\pm\) 0.36 & 0.56 \(\pm\) 0.32 & \(-\)0.08 \(\pm\) 0.11 d & \(<\)0.001 \\ VT-FFR-ES & 0.60 \(\pm\) 0.34 & 0.46 \(\pm\) 0.28 & \(-\)0.13 \(\pm\) 0.14 & \(<\)0.001 \\ \hline \hline \end{tabular} Control: no function of VT-FFR-ES; VT: vision training; FFR: frequency following response; ES: electrical stimulation. a paired _t_-test b Control _>_ VT-FFR c Control _>_ VT-FFR-ES d VT-FFR _>_VT-FFR-ES by repeated-measures ANOVA with least significant difference post hoc test.  
\end{table}
Table 2: The logMAR visual acuity of pre–post-evaluation of single intervention (n = 54 eyes).  
Figure 3: The identity plot presents the distribution of pre- and post-individual logMAR visual acuity between the single Control and VT-FFR-ES intervention types. The upper half of the identity line means a worse visual acuity than the baseline; the lower half of the identity line means a better visual acuity than the baseline. VT-FFR-ES: vision training, frequency following response and electrical stimulation; Control: no function group of VT-FFR-ES. Paired _t_-test NS, non-significant and \(p\) \(<\) 0.001.  
Identity plot between pre- and post-test spherical equivalents between the Control group and vision training with frequency following response and electrical stimulation group (VT-FFR-ES) for 4 weeks.