LCA2 is an ideal target for gene therapy because RPE65 encodes an enzyme expressed in the RPE layer, which is better targeted by AAV vectors than PRs (12); in addition,RPE65 deficiency causes severe hypovision with a reasonably preserved retinal structure for 2–3 decades (39), which gives gene therapy the opportunity to restore visual function rather than preventing photoreceptor loss, as in many other purely degenerative IRDs. This evidence concerns the gene RPE65 and respiratory distress syndrome in premature infants.