Dynamic contour tonometry in primary open angle glaucoma and pseudoexfoliation glaucoma: Factors associated with intraocular pressure and ocular pulse amplitude

Abstract

Purpose:To compare the intraocular pressures (IOP) and ocular pulse amplitudes (OPAs) in patients with primary open-angle glaucoma (POAG) and pseudoexfoliation glaucoma (PXG), and to evaluate ocular and systemic factors associated with the OPA.Materials and Methods:In this prospective study, on 28 POAG and 30 PXG patients, IOP was measured with the Goldmann applanation tonometry (GAT) and the Pascal dynamic contour tonometry (DCT). Other measurements included central corneal thickness (CCT), vertical cup-to-disc ratio (CDR), and systolic and diastolic blood pressure. Statistical significance was defined as P < 0.05.Results:In each of the POAG and PXG groups, GAT IOP was correlated with CCT (r = 0.40, P = 0.03 and r = 0.35, P = 0.05, respectively), whereas DCT IOP and CCT were not correlated. In all patients and in the POAG group, OPA was positively correlated with DCT IOP (r = 0.39, P = 0.002). OPA was not correlated with CCT in the POAG (P = 0.80), nor in the PXG (P = 0.20) group, after adjusting for DCT IOP. When corrected for DCT IOP and CCT, there was a significant negative correlation between OPA and vertical CDR in all patients (r = −0.41, P = 0.002). There was no significant difference in OPA between groups (P = 0.55), even when OPA was adjusted for IOP and systolic and diastolic pressure (P = 0.40), in a linear regression model.Conclusion:DCT IOP and OPA are not correlated with CCT. There is no significant difference between the OPA of PXG and POAG eyes. OPA is correlated with DCT IOP, and is lower in eyes with more advanced glaucomatous cupping.