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 1mmHg 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 μm).
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.
