Dynamic contour tonometry and Goldmann applanation tonometry: correlation with intracameral assessment of intraocular pressure

PURPOSE. To compare intraocular pressure (IOP) measured using a dynamic contour tonometer (DCT) and a Goldmann applanation tonometer (GAT) with in vivo intracameral IOP, and establish the relationship between DCT GAT and central corneal thickness (CCT) in patients with primary open-angle glaucoma (POAG). MATERIALS AND METHODS. We examined 50 eyes of 50 patients with POAG scheduled for glaucoma or cataract surgery. Immediately before surgery, CCT, GAT and DCT IOP were assessed, after which manometry of the anterior chamber was performed. A Bland-Altman plot was used to test the agreement among the 3 measurements of IOP, and univariate and multivariate regression analyses were used to evaluate the effect of CCT on DCT and GAT RESULTS. On average, the DCT readings were 4.0 +/- 1.6 mmHg higher than the GAT readings and 2.3 +/- 2.4 mmHg higher than the manometric readings; the GAT measurements were generally a mean 1.7 +/- 1.8 mmHg lower than the manometric readings. The CCT had an almost similar influence on DCT and GAT measurements (p=0.84). CONCLUSIONS. The DCT-measured IOP was significantly higher than that measured by means of GAT and anterior chamber manometry. The DCT and GAT readings were both influenced by CCT to the same extent.