CDKN2B-AS1 and glaucoma: Although the mechanisms by which different loci influence the development of glaucoma are uncertain, there are at least two potential reasons to account for the conflicting results for the association between optic nerve head blood flow and the risk alleles in CDKN2BAS-1 and SIX6. First, the risk alleles may confer the RGCs to become more sensitive to reduced ocular circulation.