In accordance, hypoxia, as assayed by pimonidazole immunolabel, was largely absent in the ON and ONH with comparably low labeling in control and the bead glaucoma model after 2 weeks and 4 weeks of IOP elevation; however, there was a significant increase in Hif-1α transcript after 4 weeks of OHT. This evidence concerns the gene HIF1A and glaucoma.