PDE6B and glaucoma: It was reported that GDNF can be produced by glial cells to increase the survival rate of a retinal ganglion or photoreceptor cells in different experimental models, such as the rescue of retinal ganglion cells after axotomy (Koeberle and Ball, 1998), the delivery of a protective effect in mice with glaucoma (Johnson et al., 2011), or the protection of photoreceptors in the rd1 mouse (Frasson et al., 1999).