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Gustavo Rosa Gameiro, Giovana Rosa Gameiro, Michel Eid Farah, Jianhua Wang, Paulo Schor; Retinal vessel density changes associated with the water drinking stress test. Invest. Ophthalmol. Vis. Sci. 2020;61(7):613.
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© ARVO (1962-2015); The Authors (2016-present)
The water drinking test (WDT) is a well-known stress test that increases intraocular pressure (IOP) momentarily, and it can indicate risk of glaucoma progression. This study focuses on correlating changes in the deep retinal vascular plexus with WDT in normal subjects.
Twenty-three eyes of twenty-three healthy young subjects (mean age 24.37 ± 2.13 years) were included in this study. In our protocol, WDT consisted in drinking 1 liter of water within 5 min. Outcome measures in this prospective observational study were mean arterial pressure (MAP), heart rate (HR), IOP and retinal vessel density of both superficial and deep macular retina using optical coherence tomography angiography (OCTA), which were assessed before WDT and 4 times after at 15-min intervals. OCTA images were later quantified by fractal analysis (box counting [Dbox]. The paired-t test was used to compare measurements to baseline.
WDT resulted in significant peak changes in the following parameters at different times after the test compared to baseline: IOP: baseline 15.51 ± 3.42 mmHg, 15 min 17.00 ± 3.76 mmHg (p=0.005), 30 min 18.26 ± 4.62 (p<0.0001), 45 min 17.46 ± 4.29 (p=0.001); MAP: baseline 94.17 ± 15.74 mmHg, 60 min 90.53 ± 12.31 mmHg (p=0.031); HR: baseline 75.74 ± 12.23 bpm, 15 min 64.95 ± 11.37 bpm (p<0.0001), 30 min 65.26 ± 10.82 (p<0.0001); 45 min 68.79 ± 10.59 bpm (p=0.001); 60 min 70.68 ± 11.81 bpm (p=0.007). Dbox of deep vascular plexus: baseline 1.755 ± 0.01, 15 min 1.745 ± 0.02 (p=0.004). Dbox of superficial vascular plexus did not change in our study.
Besides IOP elevation and systemic effects on blood pressure and heart rate, WDT is associated with temporary modifications of the deep vascular plexus in healthy subjects. Moreover, this vascular alteration occurs in the same time course of modifications in retinal ganglion cell function (J Glaucoma 2018, 27(5):429-432).
This is a 2020 ARVO Annual Meeting abstract.
Table 1. IOP, MAP, HR and retinal vessel density measurements in 23 healthy subjects after WDT. IOP: Intraocular pressure, MAP: mean arterial pressure, HR: heart rate, WDT: water drinking test.
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