Why is Wei Zi blind?

They continued to flee south and came to the suburbs. They met a group of men in black. These men in black are different from those in the last raid. This time, it was a run, and Yongqi and Erkang suffered heavy losses, especially Erkang's arm was bleeding, and Wei Zi, who was blind, was surprised and afraid. Under the defense of Xiao Jian's superb martial arts, they finally repelled the enemy. Wei Zi and others took good care of the injured Erkang and Yongqi. In order to appease Erkang's injured body and mind, Wei Zi played the piano and sang songs for Erkang all night, until the sunrise turned pale, and Wei Zi miraculously saw her eyes. The crowd decided to buy art in the city streets because their money was running out.