Inclusion Criteria: * Retinal disease caused by homozygous or compound heterozygote RPE65 mutations; * Clinical diagnosis of Leber congenital amaurosis (LCA) with severely impaired visual and retinal function, and best corrected visual acuity of 20/50 or worse in the study eye; * Ability to perform tests of visual and retinal function; * Good general health; * Ability to comply with research procedures; * Specific for Cohort 1 and 2: 18 years of age and older; * Specific for Cohort 3: Over 8 years of age; Exclusion Criteria: * Immune deficiency or use of immunosuppressive medications; * Pre-existing eye conditions that would preclude the planned surgery or interfere with the interpretation of study endpoints (for example, glaucoma or ocular media opacities); * Complicating systemic diseases; * Impaired coagulation or use of anti-platelet agents within 7 days prior to study agent administration; * Pregnancy or breastfeeding; * Individuals (males and females) of childbearing potential who are unwilling to use effective contraception for 1 year following agent administration and barrier contraception for 3 months following agent administration; * Any other condition that would prevent a subject from completing follow-up examinations during the course of the study; * Any other condition that, in the opinion of the investigator, makes the subject unsuitable for the study; * Current or recent participation in any other research protocol involving investigational agents or therapies, including recent (within past 6 months) receipt of an investigational biologic therapeutic agent. Subjects will not be excluded based on their gender, race or ethnicity.