Reproducibility of the water-drinking test in patients with exfoliation syndrome and exfoliative glaucoma

PurposeTo evaluate the reproducibility of intraocular pressure (IOP) peaks and fluctuations detected during the water-drinking test (WDT) in patients with exfoliation syndrome (XFS) and exfoliative glaucoma (XFG). MethodsThis prospective study included 34 XFS and 30 XFG patients. Each patient was evaluated twice, with the two WDTs performed on a 30-day interval. We recorded IOP peak (highest IOP during the WDT) and IOP fluctuation (IOP peak minus IOP before the test). Bland-Altman analysis was applied to assess the agreement of IOP peaks and fluctuations between the two consecutive visits. We defined reproducible as within 4 mmHg for IOP peak and within 2 mmHg for IOP fluctuation. ResultsThere were no significant differences in IOP values, IOP peaks and IOP fluctuations between the two visits for both XFS and XFG patients (p>0.05, for all). The coefficient of repeatability for IOP peak was 2.5mmHg and 3.5mmHg in XFS and XFG patients respectively and for IOP fluctuation, it was 2.1mmHg and 2.2mmHg. None of the XFS or XFG patients had an IOP peak difference higher than 4mmHg. Intraocular pressure (IOP) fluctuation differences above 2.0mmHg were found in 8.8% of XFS patients and 16.6% of XFG patients. ConclusionsIntraocular pressure (IOP) peak and IOP fluctuation have a reproducibility, both in XFS and in XFG.