With the beep leading (
Fig. 1), there was no significant difference in illusion strength between participants with amblyopia and visually normal controls in all three viewing conditions (binocular:
F1,25 = 0.21,
P = 0.65; dominant/fellow eye:
F1,25 = 0.14,
P = 0.71; and nondominant/amblyopic eye:
F1,25 < 0.1,
P = 0.98). As expected, there were main effects of SOA with decreasing illusion strength as SOA increased for all viewing conditions (binocular:
F2,50 = 15.9,
P < 0.001; dominant/fellow eye:
F2,50 = 24.7,
P < 0.001; and nondominant/amblyopic eye:
F2,50 = 12.7,
P < 0.001). Importantly, there was an interaction of group and SOA for the binocular viewing condition (
F2,50 = 5.49,
P = 0.007). Post hoc testing revealed that the illusion strengths at SOAs of 200 milliseconds and 100 milliseconds were significantly different from that at SOA of 0 milliseconds for the visually normal group (
P < 0.001), but not for the amblyopia group, indicating a widening of the temporal binding window in amblyopia during binocular viewing only. There were no interactions of group and SOA for the dominant/fellow eye (
F2,50 = 1.48,
P = 0.24) or nondominant/amblyopic eye (
F2,50 = 1.97,
P = 0.15) viewing conditions.
Similarly, with the flash leading (
Fig. 2), no significant difference in illusion strength was found between participants with amblyopia and visually normal controls in all three viewing conditions (binocular:
F1,25 < 0.1,
P = 0.99; dominant/fellow eye:
F1,25 < 0.1,
P = 0.79; and nondominant/amblyopic eye:
F1,25 < 0.1,
P = 0.80). There were also main effects of SOA for all viewing conditions (binocular:
F2,50 = 8.09,
P < 0.001; dominant/fellow eye:
F2,50 = 20.1,
P < 0.001; nondominant/amblyopic eye:
F1.59,39.7 = 10.5,
P < 0.001). In contrast to beep leading, there were no interactions of group and SOA for any of the three viewing conditions (binocular:
F2,50 = 1.43,
P = 0.25; dominant/fellow eye:
F2,50 = 0.53,
P = 0.59; and nondominant/amblyopic eye:
F1.59,39.7 = 0.30,
P = 0.74).