NTRK1 and ocular hypertension: PDGF-AA is a ligand for the PDGF receptor and a member of the receptor tyrosine kinase family.[19] Previously, Chong et al identified PDGF-AA as a novel neuroprotective factor protecting RGC in retinal explant cultures and in a laser-induced ocular hypertension model of glaucoma.[20,21] PDGF-AA may promote RGC survival through a direct effect on the PI3 kinase/AKT pathway, which prevents cell death.[22] Compared with the CG, there was no difference among the three types of glaucoma.