Purpose: Functional magnetic resonance imaging (fMRI) is the most advanced neuroimaging technique. The aim of this study was to investigate the blood oxygenation level-dependent (BOLD) of V1 and V2 visual cortex in anisometropic amblyopia with fMRI and explore the neural mechanism of amblyopia.
Methods: fMRI was performed with a 3.0-T MRI scanner during reversal checkerboard visual stimulation with different spatial frequencies (SF) of 0.4, 2, and 8 cpd in 2 states of temporal frequencies (TF) of 6 Hz and 8 Hz in a group of patients with anisometropic amblyopia (n=5) and a group of normal observers (n=4). Data were processed by SPM software offline. Responses of different eyes were compared in different conditions.
Results: The BOLD signal magnitude in V1 and V2 visual cortex of amblyopic eyes was significantly lower than the fellow eyes with anisometropic amblyopia at low SF (0.4-2 cpd) (p<0.05), but it was significantly higher than the fellow eyes at high SF (8 cpd) (p<0.05). The BOLD signal magnitude in V1 and V2 visual cortex of amblyopic eyes was significantly lower than the nondominant eyes in normal subjects in all conditions (p<0.001).
Conclusions: There are cortical deficits in V1 and V2 visual cortex of anisometropic amblyopia, which may be useful for selecting an optimum stimulus at proper temporospatial frequency.