Pharmacological interventions to treat some forms of retinal disease have been attempted in animal models of human blinding conditions, among them treatment of rd1 mice with the Ca2+ channel blocker D-cis-diltiazem and other blockers that prevent rise of intracellular Ca2+ to toxic levels [31], and treatment of rd1 mice with leukemia inhibitory factor, which is involved in the down-regulation of genes involved in synthesis and degradation of cGMP [32]. This evidence concerns the gene PDE6B and Abnormal retinal morphology.