Prostaglandin D2 synthase (PTGDS; down regulated in POAG LC cells) has an antihypoxic effect in mice [25] which together with thrombospondin-1 upregulation was intriguing in the context of hypoxic insult and vascular hypoperfusion of the optic nerve head in POAG. This evidence concerns the gene THBS1 and open-angle glaucoma.