ATF4 and glaucoma: In addition, CCT020312 administration abolished valdecoxib’s protective effect, activated the expression of p-PERK, ATF4 and CHOP and aggravated ER stress-mediated apoptosis in the OGD/R model, indicating that the inhibition of the PERK-ATF4-CHOP pathway was required for valdecoxib’s protective effect on glaucoma.