SLC4A4 and low tension glaucoma: Because NBCe1 in retinal Müller cells may protect against excessive synaptic activity by counteracting the light-induced extracellular alkalosis (Borgula et al., 1989; Newman, 1999), the dominant-negative effect of S982NfsX4 in retina may be responsible for normal-tension glaucoma found in the heterozygous family members.