Correlation between intraocular pressure obtained with water drinking test versus modified diurnal tension curve measurement in pseudoexfoliation glaucoma

Purpose The aim of this paper was to study the correlation and agreement between the intraocular pressure (IOP) peak value and fluctuations detected with the modified diurnal tension curve (mDTC) and the water drinking test (WDT) in pseudoexfoliation glaucoma (XFG) patients. Methods This prospective observational study enrolled 42 eyes of 42 XFG patients. The IOPs were measured at 2-h intervals from 8 am to 4 pm with a Goldmann applanation tonometer by a single observer to establish the mDTC. The WDT was then performed between 4 and 5 pm on the same day and the IOP was measured 4 times at 15-min intervals after water ingestion. The IOPpeak, IOPmean, IO (min), and IOPfluctuation were measured with both the mDTC and WDT. The paired sample t test, Spearman's correlation coefficient and Bland-Altman plots were used for statistical analysis. Results The mean age of the 42 patients consisting of 24 females and 18 males was 66.9 +/- 6.8 years, and the mean central corneal thickness was 517.7 +/- 29.1 mu m. The mean values with the mDTC and WDT measurements were 15.05 +/- 2.75 mmHg and 17.17 +/- 3.25 mmHg (p <= 0.0001, r = 0.884) for IOPmean, 16.76 +/- 3.45 mmHg and 18.92 +/- 3.94 mmHg (p <= 0.0001, r=0.787) for IOPpeak, and 13.61 +/- 2.56 mmHg and 15.11 +/- 2.84 mmHg (p <= 0.0001, r=0.824) for IOPmin, respectively, and a positive correlation was present between these values. Conclusion There was a positive correlation between the peak, minimum, and mean IOP values determined using the mDTC and WDT in treated XFG patients. WDT can be used as an alternative in the assessment of the IOP in these patients as a more practical method.