Functional OCT Reveals Anisotropic Changes of Retinal Flicker Evoked Vasodilation

A custom-built optical coherence tomography (OCT) was used for time-lapse imaging of mouse retinas with flicker stimulation. Stimulus-evoked vessel lumen changes of individual arteries and veins were quantitatively evaluated. Comparative analysis revealed significantly larger (18.21%) lumen dilation in axial direction compared to lateral (10.77%) direction. The axial lumen dilation predominantly resulted from the top vessel wall movement toward the vitreous direction, whereas the bottom vessel wall remained stable. Additional Doppler OCT analysis confirmed velocity increase corresponding to retinal flicker stimulation. The blood flow area expansion was consistently observed to be larger in axial direction compared to that in lateral direction.