We thank De Moraes and associates for their interest in our editorial and this contribution to the ongoing discussion of the water drinking test. The reasons to perform the WDT as well as its clinical usefulness in assessing the therapeutic effectiveness of intraocular pressure-lowering strategies, as we described, agrees totally with the points they raise. Since we wrote our editorial, De Moraes and associates have demonstrated choroidal thickening as a potential mechanism for the WDT-induced intraocular pressure response. It is a welcome contribution to the literature on the physiology of WDT, and we support this opportunity to highlight it for your readers. Even with this useful addition to our knowledge, our understanding of the physiological basis for the WDT remains incomplete. It bears repeating: further research into the WDT is needed to understand better its physiology and clinical application.