GFAP and ischemia: It has been noted that astrocytes are the only cells in the retina that express GFAP, but after various insults such as retinal detachment, ischemia, light damage, or genetic photoreceptor degeneration, Müller glia become GFAP-positive [49], [50], whereas Normoxic Retinas expressed low levels of GFAP expression that was confined to the ILM and GCL regions of the retina, with no Müller cell processes staining.