The efficacy of both oversized and dual AAV vectors in the retina has been evaluated in a number of studies using different reporter and therapeutic genes, such as ABCA4 and MYO7A mutated in Stargardt disease (STGD1) [31] and Usher syndrome type 1B (USH1B) [32], respectively. This evidence concerns the gene MYO7A and severe early-childhood-onset retinal dystrophy.