Leber congenital amaurosis (LCA) is a rare inherited retinal disease present from birth that causes severe vision loss. It is caused by mutations in genes critical for the visual cycle, preventing the retina from responding normally to light. Diagnosis involves assessing lack of retinal response on electroretinogram and genetic testing to identify the specific mutation. While currently no treatment can restore lost vision, gene therapy targeting the RPE65 gene has been approved for LCA type 2 based on clinical trials demonstrating improved light sensitivity.