Glaucoma is a disease of the optic nerve that can eventually progress to blindness. The article on glaucoma in Wikipedia discusses the many forms known.
SNPs in several genes have been linked to increased risk for glaucoma, including MYOC (specifically, rs28936694), OPTN and WDR36. Based on GWAS studies, a very strong association was reported in Icelandic and Swedish populations for a haplotype consisting of two SNPs in the LOXL1 gene, rs1048661 and rs3825942. [PMID 17690259]
Forms of glaucoma and the genes in which mutations are for them are known include: