GFAP and glaucoma: In mice with DEX-induced glaucoma, an up-regulation of retinal GFAP was observed to extend through all retinal layers, including the inner plexiform layer (IPL), inner nuclear layer (INL), outer plexiform layer (OPL), and some processes even extended up to the photoreceptor layer (ONL), thus indicating Müller cells activation (Figure 2E).