Previously, the potency of gene therapy vectors for the treatment of CNGA3- or CNGB3-linked achromatopsia was assessed after subretinal or intravitreal injection of the gene therapy vector in gene-deficient animal models (i.e., mouse or dog) [3,4,5,6,7,8,9,10]. This evidence concerns the gene CNGB3 and achromatopsia.