In the course of this astrogliosis in glaucoma, there is also increased expression of the phagocytosis-related Mac-2 gene and ET-1 by astrocytes, demonstrating both their role in phagocytosis of damaged or dead RGC debris and their involvement in glaucoma-associated vascular dysregulation (Nickells et al., 2012; Chong and Martin, 2015). This evidence concerns the gene EDN1 and glaucoma.