3.1 Threshold intensity
The ANOVA result indicated a significant AM main effect (F (1,24)
= 26.505, p < 0.001,
ηp2 = 0.525), showing that the
phosphene threshold for AM stimulation (mean value with 95% CI: 1284.12
± 42.10) was significantly higher than for sinusoidal stimulation
(1080.96 ± 86.90). We did not observe a main effect of polarity
(F (2,48) = 0.716, p = 0.494,
ηp2 = 0.029) or the interactions
between polarity and AM (F (2,48) = 0.653, p = 0.525,
ηp2 = 0.026; Figure 2A).