Abstract
Purpose :
Tonometry is a crucial method to manage glaucoma. Rebound tonometers are recent options to determine IOP values. The aim of the current study is to compare three different devices in assessing IOP among glaucoma patients and glaucoma suspects.
Methods :
IOP values were prospectively compared in a random order of consecutive patients visiting a glaucoma center. Measurements were performed by the Goldmann applanation tonometry (GAT), ic100 Icare rebound tonometry (ic100 RT) and TAO1i Icare rebound tonometry (TA01i RT) in eyes in which a battery of glaucoma testing was done. Agreement between measurements was calculated per eye with coefficient of variation (CV), correlation analysis (intraclass and confidence), and Bland-Altman plots. Correlation of keratometry and central corneal thickness (CCT) on IOP measurements was assessed with Pearson's correlation coefficient.
Results :
Forty five eyes of 46 patients (mean age 66.1±11.2 years, 35 females; mean CD ratios RE 0.74±0.19/LE 0.73±0.19; mean CCT RE 537.1±30.1 microns/LE 533.5±35.2 microns) were included in this study. Non-significant differences of coefficient of variation were noted between eyes (RE vs. LE): GAT (31.2% vs. 36.8%), ic100 RT (34.2% vs. 48.2%), TA01i RT (32.1% vs. 43.2%). Both intraclass and confidence coefficient values were excellent for the three tonometric methods in each eye (RE, 0.86, CI: 0.79-0.91; LE, 0.92, CI: 0.87-0.95; RE, > 0.84; LE > 0.87, respectively). Strong and significant correlations were found among the three devices: GAT and ic100 RT (RE, r=0.85, P<0.0001; LE, r=0.90, P<0.0001), GAT and TA01i (RE, r=0.88, P<0.0001; LE, r=0.93, P<0.0001), ic100 RT and TA01i (RE, r=0.87, P<0.0001; LE r=0.96, P<0.0001). Bland-Altman plots were compatible with no consistent bias when Icare devices were compared against GAT. Mean IOP values measured by Icare devices (ic100 RT: RE, 14.0±4.8 mmHg, LE, 14.7±7.1 mmHg; TA01i RT: RE, 14.3±4.6 mmHg; LE, 15.2±6.6 mmHg) were non-significantly different than those obtained with GAT (RE, 14.7±4.7 mm Hg; LE, 14.8±5.5 mm Hg). CCT and astigmatism did not have significant impact on IOP measurements.
Conclusions :
IOP measurements with three different techniques (GAT, iC100 rebound tonometry and TA01i rebound tonometry) demonstrated very good correlations and non-significant pressure measurements in both eyes of Latino patients attending a specialized glaucoma center.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.