An Open-label, Dose Escalation and Double-masked, Randomized, Controlled Trial Evaluating Safety and Tolerability of Sepofarsen in Children (<8 Years of Age) With LCA10 Caused by Mutations in the CEP290 Gene.

Inclusion Criteria: * Male or female child, \<8 years of age at Screening with a clinical diagnosis of LCA and a molecular diagnosis of homozygosity or compound heterozygosity for the CEP290 p.Cys998X mutation, based on genotyping analysis at Screening. A historic genotyping report from a certified laboratory are acceptable with Sponsor approval. * BCVA equal to or better than Logarithm of the Minimum Angle of Resolution (logMAR) + 4.0 (Light Perception), and equal to or worse than logMAR + 0.4 in the treatment eye. * Detectable outer nuclear layer (ONL) in the area of the macula. Exclusion Criteria: * Presence of any significant ocular or non-ocular disease/disorder which may put the subject at risk because of participation in the trial' may influence the results of the trial, or the subject's ability to participate in the trial. * Receipt within 1 month prior to Screening of any intraocular or periocular surgery (including refractive surgery), or an IVT injection or planned intraocular surgery or procedure during the course of the trial. * Current treatment or treatment within the past 12 months with therapies known to influence the immune system (including but not limited to cytostatics, interferons, TNF-binding proteins, drugs acting on immunophilins, or antibodies with known impact on the immune system). * Current treatment or treatment within the past 3 months or planned treatment with drugs known to be toxic to the lens, retina, or the optic nerve. * Use of any investigational drug or device within 3 months or 5 half-lives of Day 1, whichever is longer, or plans to participate in another study of a drug or device during the trial period. * Any prior receipt of genetic or stem-cell therapy for ocular or non-ocular disease.