Dynamic contour tonometry (DCT) versus Goldmann applanation tonometry (GAT) - a comparison of agreement and reproducibility

Background

The PASCAL® dynamic contour tonometer (DCT) is a novel device designed for intraocular pressure (IOP) measurements. It is assumed to be largely independent of corneal properties. In a previous study we compared DCT with Goldmann applanation tonometry (GAT) in 100 right eyes with normal corneas. The aim of the present study is to evaluate whether differences DCT-GAT?≥?2.0 mmHg found in the previous study are reproducible and also present in the fellow eye.

Methods

Twenty-three of the 100 patients (M:F?=?8:15, mean age: 36?±?11 SD, range 22–53 years) with a previous difference DCT-GAT?≥?2.0 mmHg were included in the present study. The minimum interval between the initial and the current examination was 3 weeks. The IOP-values of the fellow eyes in this subgroup were assessed in parallel.

Results

The difference DCT-GAT was 2.44?±?0.4 SEM mmHg in the subgroup of the 23 right eyes and 2.03?±?0.5 SEM mmHg for the fellow eyes, compared to 0.94?±?0.5 SEM mmHg in the initial sample of 100 eyes.

Conclusions

In cases with higher difference between DCT-GAT, the difference is reproducible and even present in the fellow eye. We, therefore, assume that the differences are not caused by chance, but by differing biomechanical corneal properties.