Figure 2. Comparisons of all measurement indices. (A) The phosphene threshold results were averaged across the anodal otDCS, cathodal otDCS, and tACS conditions, with the error bars representing 95% confidence intervals. Phosphene thresholds for AM stimulation were found to be higher than those for sinusoidal stimulation. (B) The graph presents the mean phosphene reaction time, with the solid line representing the threshold intensity (100%) and the dashed line indicating the suprathreshold intensity (120%). Phosphene reaction times for tACS were faster compared to those for cathodal otDCS. Additionally, reaction times in sinusoidal trials were faster than in AM trials, and they were quicker under suprathreshold conditions compared to threshold conditions. (C) The flash brightness scoring results indicated that participants perceived phosphene as being more absent at threshold intensity than at suprathreshold intensity. (D) The graph displayed the mean flash rate scoring. The results showed that AM dominated in both otDCS and tACS conditions. (E) The results showed that participants displayed greater confidence levels when responding to suprathreshold stimulation than threshold stimulation. This difference was particularly apparent in the AM stimulation during anodal otDCS and in the sinusoidal stimulation in tACS. (F) Drawings of phosphene size for sinusoidal stimulation were significantly larger than those for AM stimulation. Likewise, phosphene areas produced at suprathreshold intensities were apparently larger than those at threshold intensities. In addition to the results that both otDCS and tACS did not influence the phosphene size, exceptions were observed for both AM and intensity levels.