Abstract
Purpose: :
The Water Drinking Test (WDT) has been used to evaluate the effect of treatment on reducing intraocular pressure (IOP) peak and fluctuation, both with ocular hypotensive medications and filtering surgery. However, in order to be useful, a test must provide reproducible results with consistent measurements. This study was performed to verify the reproducibility of peak and fluctuation of IOP elicited by the WDT in treated patients with primary open-angle glaucoma (POAG).
Methods: :
Retrospective analysis of 34 eyes from 34 treated POAG patients submitted to the WDT performed in two visits within six months period. All patients were attended sequentially during one week and none of the patients changed own therapeutic regiment. Reproducibility of peak (maximum IOP) and fluctuation (difference between peak and baseline IOP) was assessed using the interclass correlation coefficient (ICC). The IOP was measured before the ingestion of water and after drinking 800 ml of tap water in five minutes. IOPs are then measured 15 minutes, 30 minutes and 45 minutes after the ingestion of the water. No fluid ingestion was allowed two hours prior to the WDT.
Results: :
Test and retest IOP peak values were 14.55±3.41 and 15.01±3.66 mmHg respectively (ICC = 0.85, p<0.001). Test and retest IOP fluctuation values were 2.82±1.99 and 3.41±2.54 mmHg, respectively (ICC = 0.50, p<0.001).
Conclusions: :
IOP peaks detected during WDTs six months apart in treated glaucomatous individuals presented excellent reproducibility, whereas the reproducibility of fluctuation was fair. This should be taken into account when using this test in researches as well as for glaucoma management.
Keywords: intraocular pressure