To determine whether DDIT3 and JUN control death of RGC axons after ocular hypertension, D2.Ddit3/Jun−/− and WT D2 control optic nerves were assessed for axonal degeneration at 12 M—a timepoint at which roughly 50% of D2 optic nerves will have severe optic nerve damage [47]. The gene discussed is DDIT3; the disease is ocular hypertension.