HDAC9 and retinal ischemia: For example, the application of valprioc acid, a class I and IIa HDAC inhibitor, or trichostatin A (TSA), a pan-HDAC inhibitor, was reported to be neuroprotective in retinal ganglion cells (RGC) in an animal model of optic nerve crushing, retinal ischemia, and chronic ocular hypertension [5,6,7,8].