Short-term amblyopic eye deprivation boosts the binocular intermodulation in anisometropic amblyopia

Purpose We tested whether short-term monocular deprivation (STMD) of the amblyopic eye enhances binocular intermodulation steady-state visual evoked potentials (SSVEPs), reflecting reduced suppression from the fellow eye. Methods Fifteen anisometropic amblyopes (15.6 ± 5.8 years) underwent 2-h STMD of their fellow eye on the first day, followed by a similar session on their amblyopic eye on the second day. We recorded SSVEPs from 21 occipital electrodes pre/post STMD during binocular rivalry (6/7.5 Hz flicker). Results Similar to the previous study, the monocular SSVEP amplitude of the deprived eye increased after STMD, whereas that of the non-deprived eye remained unchanged. Critically, STMD of the amblyopic eye significantly increased f 1 +f 2 intermodulation amplitude ( t = 2.42, pFDR = 0.030), while STMD of the fellow eye showed no such effect ( p > 0.05). Baseline f 1 +f 2 amplitude was strongly correlated with the magnitude of SSVEP change following STMD ( r = 0.789, p < 0.001). Conclusion STMD of the amblyopic eye, but not the fellow eye, significantly enhanced binocular SSVEP intermodulation. Baseline f1+f2 amplitude predicted the magnitude of plasticity, suggesting its potential as an electrophysiological biomarker for reverse deprivation therapy.