Several retinal disease-related genes absent in cells transduced with CRX alone were also significantly detected (Fig. 4B, Fig. 5) in cells transduced with CRX before NeuroD1 or those transduced with RAX1+CRX before NeuroD1 in a modified medium containing Activin A, Dkk, and Lefty2 or the RPE-conditioned medium. Here, LEFTY2 is linked to Abnormal retinal morphology.