Halo 194 (Jan 2020)
The impact of central corneal thickness on values of intraocular pressure measured using two methods: Goldmann applanation and dynamic contour tonometry in patients with open-angle glaucoma
Abstract
Introduction Dynamic contour tonometry (DCT) is a contact, non-applanation method for measuring intraocular pressure (IOP). Objektive The study aimed at evaluating the impact of central corneal thickness (CCT) on values of IOP measured using two methods: Goldmann applanation tonometry (GAT) and DCT. Methods The study included 150 patients (300 eyes) with the diagnosis of open-angle glaucoma (54 males) and mean age of 59.39± 13.12 years. IOP was measured using two methods: GAT and DCT. CCT was measured (ultrasound pachymetry). DCT introduced a new value - the ocular pulse amplitude (OPA). Results The IOP measured with the GAT was lower compared to the IOP measured with DCT (17.71±3.35mmHg vs 19.80± 3.67mmHg). There was a significant positive correlation between IOP measured with GAT and IOP measured with DCT (r= 0.867, p< 0.01). In all patients, there was a significant positive correlation between CCT and IOP measured with GAT (r=0.198, p< 0.01), as well as between CCT and IOP measured with DCT (r=0.180, p< 0.05). With every 10mm of change in CCT, the change of IOP measured with GAT was 0.3mmHg, while the average change of IOP measured with DCT was 0.4 mmHg. There was a significant positive correlation between CCT and OPA (r=0.204, p< 0.01). There was also a significant positive correlation between OPA and IOP measured with GAT (r= 0.393, p< 0.01) and between OPA and IOP measured with DCT (r= 0.452, p< 0.01). Conclusion IOP measured with GAT was lower than IOP measured with DCT. CCT had impact on both methods: GAT and DCT. The impact of CCT on IOP (DCT) was lower compared to the impact of CCT on IOP(GAT).
