Clinical Study
Eye (2006) 20, 191–198. doi:10.1038/sj.eye.6701849; published online 1 April 2005
Comparison of intraocular pressure measured by Pascal dynamic contour tonometry and Goldmann applanation tonometry
J Y F Ku1, H V Danesh-Meyer1, J P Craig1, G D Gamble2 and C N J McGhee1
- 1Department of Ophthalmology, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
- 2Department of Medicine, Faculty of Medical and Health Sciences, University of Auckland, Auckland, New Zealand
Correspondence: CNJ McGhee, Department of Ophthalmology, Private Bag 92019, The University of Auckland, Auckland, New Zealand. Tel: +64 9 373 7599 ext 86712; Fax: +64 9 367 7173; E-mail: c.mcghee@auckland.ac.nz
Received 19 September 2004; Accepted 5 January 2005; Published online 1 April 2005.
Abstract
Aims
To compare the intraocular pressure (IOP) measurements obtained using the Pascal dynamic contour tonometer (PDCT) with the standard Goldmann applanation tonometer (GAT) and to correlate these with central corneal thickness (CCT) in patients with normal corneas.
Methods
A prospective, masked, comparative case series of 116 eyes from patients attending a glaucoma clinic. IOP was measured with PDCT by one examiner and with GAT by a masked, independent examiner. A mean of six CCT readings was used for analysis.
Results
IOP measured by the two instruments correlated significantly (r=0.77; P<0.0001). IOP measured by GAT correlated strongly with CCT (r=0.37, P=0.0001) whereas the relationship between IOP measured by PDCT and CCT approached significance (r=0.17, P=0.073). The differences between GAT and PDCT measured IOP also correlated strongly with CCT (r=0.37, P<0.0001). The 95% limits of agreement between GAT and PDCT were 
4.2 mmHg. Dividing the eyes into three groups on the basis of CCT, demonstrated those in the thickest tertile showed a poorer agreement between instruments and the GAT measured significantly higher IOP in this group (P=0.003) while the PDCT showed no significant differences with different CCTs (P=0.37).
Conclusion
Demonstration of the relative independence of PDCT IOP measurements from CCT supports a potential clinical role for this instrument, particularly for subjects with CCT outside the normal range.
Keywords:
tonometry, intraocular pressure, corneal thickness
