Table 1 gives the details of the mapped genetic loci of PCG with nomenclature of the loci (GLC acronym for glaucoma; numerals indicating type and alphabets the order of discovery). Table 1 also mentions names of the genes that have been identified till date. Among the loci identified GLC1A (myocilin), GLC1E (optineurin) for POAG and GLC3A (CYP1B1) for PCG have been characterized.19-21. This evidence concerns the gene OPTN and open-angle glaucoma.