Visible light is a treatment option for Segmental Vitiligo (SV), and visible light-induced repigmentation is associated normalization of sympathetic. Currently it is difficult to predict individual patients response to visible light therapy. Therefore, the present invention uses the Laser Doppler Flowmeter to serve as a response predictor for visible light on treating SV. The present invention recruited 14 Segmental Vitiligo patients for evaluating clinical information. FirstLaser Doppler Flowmeter was used to evaluate the cutaneous blood flow of SV lesion and contralateral normal skin, and then treated them with visible light irradiate, cold-stress, rewarmed, and recorded the change of skin blood flow, finally the patients received regular visible light treatment for 3 months, and patients have a sign of repigmentation after the treatment.
