Clinical assessment of dynamic contour tonometer

Abstract

To assess the applicability and reliability of Dynamic Contour Tonometry (DCT) in the measurement of intraocular pressure (IOP) and ocular pulse amplitude (OPA) in patients with primary open-angle glaucoma (POAG), ocular hypertension (OHT), normal tension glaucoma (NTG) and normal controls. 120 subjects were included in the present study as follows: 30 patients in each group, total four groups, i. e. , POAG, OHT, NTG and normal control. IOP measured by DCT was compared to that by Goldmann applanation tonometry (GAT). OPA, central cornea thickness (CCT), central cornea curve (CCV), heart rate (HR), systolic blood pressure (SBP) and diastolic blood pressure (DBP), other associated parameters, were also determined for the subjects of each group. The IOP of all groups measured by DCT was (21.68 +/- 2.02), (23.37 +/- 2.65), (18.43 +/- 3.08), (17.04 +/- 2.07) mm Hg (1 mm Hg = 0.133 kPa); and the IOP measured by GAT was (21.18 +/- 2.95), (23.28 +/- 5.95), (16.39 +/- 3.60), (14.66 +/- 2.27) mm Hg, there was no significant differences between the IOP measured by these two methods (t = 1.338, 1.445, 1.682, 1.803; P = 0.197, 0.151, 0.136, 0.081). Significant differences of OPA levels in different groups were observed (F = 21.311, P = 0.000). OPA reading was affected by HR, SBP, DBP, IOP and CCT, while there was no correlation with patients' age. Regarding to the IOP measurement, DCT was in concord with GAT readings. The differences in OPA among POAG, OHT and the normal groups and the lowest OPA reading in NTG patients indicate different intraocular hemodynamic status among these groups. OPA measurement may be useful to early detection and progression follow-up of glaucoma patients.