Purpose: To investigate the association between corneal biomechanical parameters and primary open angle glaucoma (POAG) using the ocular response analyzer (ORA).Subjects and Methods: In a prospective cross-sectional study, patients seeking treatment at a glaucoma practice were screened to identify those with open angle glaucoma and visual field defects. Exclusion criteria were secondary glaucoma, opacities of refractive media, keratoconus, post LASIK, post cataract extraction and post glaucoma surgery. The study was done in ophthalmology polyclinic in Memorial Institute Of Ophthalmic Research in Giza.Visual Fields: VF testing was performed with static, automated perimetry ( 24-2 test pattern) using SITA- standard program.Measurement of ORA parameters: Corneal biomechanical properties were measured using the ORA, which measures two corneal biomechanical parameters CH, CRF and provides a measure of IOP that is corrected to this parameters. Corneal hysteresis CH represents '' viscous damping '' in the corneal tissue.Clinical data; Demographic details and clinical data including diagnosis, years with glaucoma, highest known IOP by Goldmann applanation tonometer, cup-to-disc ratio (CDR), CH parameters and global indices from qualifying visual field.Results: Mean corneal hysteresis (CH) was lower in the primary open angle glaucoma patients. Conclusions: Corneas in glaucomatous patients have weaker biomechanical properties.