CCN2 and glaucoma: It is known that astrocytes of the optic nerve head respond strongly to glaucomatous damage.43 In retinal diseases, the induction of GFAP in Müller cells is an early and very sensitive marker for reactive Müller cells, which is often accompanied by an increased expression of glutamine synthetase.44 Accordingly, in the eyes of human donors suffering from glaucoma, an increased expression of GFAP in Müller cells has been detected.45 In our study, the Müller glial cells showed a GFAP positive signal in the βB1‐CTGF mice in comparison to the WT littermates.