GFAP and retinal degeneration: However, another important point to consider is that Müller cells may exert both neuroprotective and detrimental effects during retinal degeneration.10, 26, 30, 31, 37 In animal models of high IOP, BMD treatment suppressed the GFAP immunoreactivity compared with the animals after treatment with timolol.43, 44 The mechanism by which BMD influences GFAP immunoreactivity is not well understood, but BMD may afford greater neuroprotection by attenuating the retinal glial reaction.