Leber Congenital Amaurosis (LCA) segmentation by type differentiates interventions according to the underlying genotype, enabling developers to size addressable niches within the overall ultra-rare patient pool. CEP290-related LCA accounts for ~35 % of diagnosed cases and anchors the market because its common c.2991+1655A>G splicing mutation is druggable with antisense oligonucleotides, creating a near-term revenue base. GUCY2D-LCA represents 20 %; although gene-replacement trials show durable efficacy, the larger coding sequence complicates vector packaging, keeping commercial uptake gradual. RPE65-LCA, already commercialized, contributes 15 % but growth is now tethered to second-generation gene-therapy safety improvements rather than patient accrual. The residual 30 % comprises twelve ultra-rare subtypes (e.g., AIPL1, CRB1, RPGRIP1) whose small populations make global development economically viable only through platform manufacturing and basket-trial regulatory strategies, collectively shaping the long-term breadth of the market taxonomy.