Dynamic contour tonometry versus Goldmann applanation tonometry: a comparative study

Abstract

Background: Various sources of error, including central corneal thickness (CCT) and structural corneal rigidity, have been proposed for Goldmann applanation tonometry (GAT). The Pascal dynamic contour tonometer (DCT) is a novel device designed for intraocular pressure (IOP) measurements assumed to be largely independent of CCT and corneal curvature. We compared DCT with GAT in eyes with normal corneas of various thickness.

Methods: We prospectively measured IOP using DCT and GAT in random order in 100 eyes of 100 subjects (M:F=46:54; mean age 42+/-19, range 23-88 years).

Results: Mean DCT values were about 1 mm Hg higher than GAT readings (16+/-3 vs 15+/-3 mmHg, p=0.001). Bland-Altman analysis of individual pairs of DCT and GAT measurements revealed a bias of -1.0 mmHg [95% confidence interval (CI): +/-1.2]. Neither GAT nor DCT showed a significant correlation with CCT (533+/-48, range 399-641 microm).

Conclusions: In eyes with normal corneas, DCT allows suitable and reliable IOP measurements which are in good concordance with GAT. Comparison of DCT with intracameral manometry is desirable in the future.