SLC23A2 and glaucoma: The only other published results on a SLC23A2 variant (rs1279683) in an eye condition also found a genotype difference in plasma ascorbate and that rs1279683 and plasma ascorbate were associated with an increased risk of primary open glaucoma.26 27 The authors concluded that the association of rs1279683 with glaucoma was directly mediated through plasma ascorbate.