BCL2 and glaucoma: Moreover, changes in expression of transcription factors such as immediate early genes (IEGs) which regulate the transcription of bax and bcl-2 genes, are observed in various experimental glaucoma models and the changes in the expression of these genes can be associated with both RGC apoptosis and survival (Kwong and Caprioli, 2006; Levkovitch-Verbin et al., 2007; Levkovitch-Verbin, 2015).