RPE65 and retinal degeneration: Although treatment effects have been observed with improved light sensitivity and mobility after subretinal administration of AAV-RPE65 gene complex in both animal models with RPE65 mutations and RPE65-LCA patients, the improved visual function started declining 3 years after treatment and this gene therapy approach could not prevent progress of retinal degeneration with photoreceptor apoptosis, which eventually leads to retinal cell loss including RPE cells and photoreceptors.