Double-masked, randomized, controlled, multiple-dose study to evaluate efficacy, safety, tolerability, and syst. exposure of QR-110 in Leber's congenital amaurosis (LCA) due to C.2991+1655A>G mutation (p.Cys998X) in the CEP290 gene. The gene discussed is CEP290; the disease is Leber congenital amaurosis.