Abstract
Purpose: :
To compare the intraocular pressures (IOPs) measured with a Goldmann applanation tonometer (GAT), a rebound tonometer (ICare; Tiolat Oy, Helsinki, Finland) in medically and/or surgically-treated glaucoma eyes with extremely low IOPs, and to determine if a significant correlation exists between the IOP and the central corneal thickness (CCT).
Methods: :
A total of 74 medically and/or surgically-treated open-angle glaucoma patients, who had an IOP with the GAT less than 10 mmHg, was examined. IOP was measured with first the ICare rebound tonometer and then with the GAT. Subsequently, the CCT was measured using an ultrasonic pachymeter.
Results: :
The mean age was 59.2 years old, and female was twenty-eight. The trabeculectomized eyes included were Forty-six. The mean IOP with the GAT and the ICare was 8.5 ± 1.8 mmHg and 9.6 ± 2.6 mmHg, respectively. There was a good correlation between the IOPs determined by the ICare and the GAT even in eyes with extremely low IOPs (P<0.001; Pearson’s correlation). However, the IOP values were significantly higher as measured by ICare than by GAT (P<0.001; paired t-test). A Bland-Altman plot showed a significant correlation between the ICare and the GAT measurements (P<0.001; Pearson’s correlation). The IOP readings with the ICare revealed statistically significant correlations with CCT (P=0.0243, r=0.261), but not between IOP values with the GAT and CCT (P=0.1763, r=0.159). On the other hand, the IOP difference between the two devices was not correlated with CCT (P=0.0568, r=0.222).
Conclusions: :
ICare rebound tonometer yields slightly higher IOP values than with the GAT even in eyes with extremely low IOPs. This discrepancy does not seem to be attributable to CCT.
Keywords: intraocular pressure • cornea: clinical science • drug toxicity/drug effects