Systemic NR also elevates retinal NAD+, preserves pattern ERG responses and retinal ganglion cell survival after optic nerve crush, limits GFAP (Glial fibrillary acidic protein) -positive gliosis, and maintains RGC counts despite intraocular pressure elevation in microbead-induced ocular hypertension [63]. This evidence concerns the gene GFAP and ocular hypertension.