Hereditary blindness caused by Leber congenital amaurosis, a condition of RPE65 mutation reducing RPE65 expression in the retinal pigment epithelium and causing severely abnormal retinal function, was reversed following intraocular injection of AAV1 and AAV2 in utero in Rpe65−/− mice at E14.127. The gene discussed is RPE65; the disease is Leber congenital amaurosis.