Much progress has been made towards improving transfection rates in the past decade, with the use of plasmids packaged into nanoparticles such as CK30PEG in the Rpe65−/− mouse model of Leber congenital amaurosis [27,28] or, more recently, the successful repeated administrations of ECO nanoparticles in the Abca4−/− mouse model of Stargardt disease [29]. This evidence concerns the gene RPE65 and Stargardt disease.