## 4 Discussion  
Most of the published studies on the evaluation of CLs for myopia control are focused on determining their efficacy for slowing the eyeball elongation according to changes in parameters such as SE and AXL. However, few of them have analyzed the real impact of the different designs of myopia control CLs on aspects such as visual acuity, visual quality or binocularity. In the current study, it was observed that the VA obtained with the EDOF CL evaluated improved as its wearing time increased. Indeed, there was an initial worsening of the VA once the lens was fitted for the first time, but the level of visual acuity was increased progressively during the first month of wearing until reaching the same level as with spectacles. This suggests that there is a period of visual adaptation with this CL of a few days (within the first 15 days of CL wear) and children fitted with this model of CL should be informed about this. On the first day of wear, the monocular far and near VA values measured in the current samples were close to those reported by [PERSON] et al. [30] who evaluated the same EOF CL (distance: 0.03 \(\pm\) 0.06; near: 0.02 \(\pm\) 0.08). In binocular tests, the study by [PERSON] et al. [31] using CLs with a concentric ring design reported slightly higher VA values for both far and near distances during the very early CL wear. Only the studies by [PERSON] et al. [32] and [PERSON] et al. [25] carried out a post-fitting follow-up of VA, not obtaining a significant visual evolution with the CL wear. Another aspect not considered in previous studies and that was analyzed in our study was the correlation between near and far VA. We found a significant positive correlation of moderate strength in the first three follow-up visits. This indicates that those children having a worse far vision at the beginning of the use of the EDOF CL evaluated tended \begin{table}
\begin{tabular}{c c c c c} \hline  & \(\mathbf{\alpha}\) & \(\mathbf{\delta}\) & \(\mathbf{\sigma}\) & \(\mathbf{n}\) & **SP** \\ \hline Monocular far VA with CL (testing day–30 days) & 0.05 & \(-0.10\) & 0.05 & 13 & 99.9\% \\ Binocular far VA with CL (testing day–30 days) & 0.05 & \(-0.08\) & 0.04 & 13 & 99.9\% \\ Monocular near VA with CL (testing day–30 days) & 0.05 & \(-0.11\) & 0.08 & 13 & 99.9\% \\ Binocular near VA with CL (testing day–30 days) & 0.05 & \(-0.09\) & 0.05 & 13 & 99.2\% \\ MEM & 0.05 & \(-0.41\) & 0.22 & 13 & 99.9\% \\ Not retinoscopy & 0.05 & \(-0.40\) & 0.32 & 13 & 98.1\% \\ HOA RMS 3 mm & 0.05 & 0.04 & 0.03 & 13 & 98.9\% \\ HOA RMS 5 mm & 0.05 & 0.06 & 0.07 & 13 & 81.0\% \\ Primary coma RMS 3 mm & 0.05 & 0.03 & 0.03 & 13 & 91.0\% \\ Primary coma RMS 5 mm & 0.05 & 0.02 & 0.07 & 13 & 14.0\% \\ SA 3 mm & 0.05 & \(-0.01\) & 0.01 & 13 & 91.0\% \\ SA 5 mm & 0.05 & \(-0.07\) & 0.07 & 13 & 91.0\% \\ Secondary astigmatism RMS 3 mm & 0.05 & 0.01 & 0.01 & 13 & 91.0\% \\ Secondary astigmatism RMS 5 mm & 0.05 & 0.02 & 0.05 & 13 & 24.0\% \\ Photopic pupil size & 0.05 & \(-0.17\) & 0.37 & 13 & 30.7\% \\ ACD & 0.05 & \(-0.04\) & 0.08 & 13 & 35.8\% \\ \hline \end{tabular}
\end{table} 
Table 5: Statistical power calculations associated with the analysis of those variables showing statistically significant changes. Abbreviations: \(\alpha\), type I error probability (probability of falsely rejecting the null hypothesis; \(\delta\), difference between means; \(\sigma\), standard deviation of difference in the response of matched pairs; \(\mathbf{n}\), number of subjects; SP, statistical power; MEM, monocular estimation method; HOA, high order aberration; RMS, root mean square; SA, spherical aberration; ACD, anterior chamber depth. to also have a worse near vision, and therefore there is a potential global limitation of the visual function of children fitted with this CL during the first days of use. Afterwards, the VA with this CL progressively improves with its use, obtaining near and far VAs like those obtained with spectacles.