PURPOSE: The purpose of the present study was to investigate whether the nucleoside adenosine is involved in the regulatory processes of choroidal blood flow (ChBF) during an experimental decrease in ocular perfusion pressure (OPP). METHODS: In this randomized, double-masked, placebo-controlled, two-way crossover study, 14 subjects received eitherintravenous adenosine or placebo on two different study days. The suction cup method was used for a stepwise increase in intraocular pressure (IOP). Subfoveal ChBF was measured by laser Doppler flowmetry. Mean arterial pressure (MAP) and IOP were measured noninvasively. Ocular perfusion pressure was calculated as OPP = 2/3MAP - IOP. RESULTS:Adenosine increased ChBF significantly versus placebo before application of the suction cup (P < 0.05). When the suction cup was applied, a significant decrease in OPP was observed. This effect was comparable on all study days. The decrease in OPP was paralleled by a significant decrease in ChBF (maximum between -43% and -52%) which was less pronounced than the decrease in OPP (maximum between -62% and -64%). Neither placebo nor adenosine influenced the ChBF increase during suction cup-induced changes in OPP. CONCLUSIONS: The data of the present study confirm that the human choroid shows some regulatory capacity during a decrease in OPP. Adenosine influences basal vascular tone in the choroid but is not involved in the regulatory mechanisms during an increase in IOP. (ClinicalTrials.gov number, NCT00712764.).
RCT Entities:
PURPOSE: The purpose of the present study was to investigate whether the nucleoside adenosine is involved in the regulatory processes of choroidal blood flow (ChBF) during an experimental decrease in ocular perfusion pressure (OPP). METHODS: In this randomized, double-masked, placebo-controlled, two-way crossover study, 14 subjects received either intravenous adenosine or placebo on two different study days. The suction cup method was used for a stepwise increase in intraocular pressure (IOP). Subfoveal ChBF was measured by laser Doppler flowmetry. Mean arterial pressure (MAP) and IOP were measured noninvasively. Ocular perfusion pressure was calculated as OPP = 2/3MAP - IOP. RESULTS:Adenosine increased ChBF significantly versus placebo before application of the suction cup (P < 0.05). When the suction cup was applied, a significant decrease in OPP was observed. This effect was comparable on all study days. The decrease in OPP was paralleled by a significant decrease in ChBF (maximum between -43% and -52%) which was less pronounced than the decrease in OPP (maximum between -62% and -64%). Neither placebo nor adenosine influenced the ChBF increase during suction cup-induced changes in OPP. CONCLUSIONS: The data of the present study confirm that the human choroid shows some regulatory capacity during a decrease in OPP. Adenosine influences basal vascular tone in the choroid but is not involved in the regulatory mechanisms during an increase in IOP. (ClinicalTrials.gov number, NCT00712764.).
Authors: Guorong Li; Karen Y Torrejon; Andrea M Unser; Feryan Ahmed; Iris D Navarro; Rudolf A Baumgartner; David S Albers; W Daniel Stamer Journal: Invest Ophthalmol Vis Sci Date: 2018-01-01 Impact factor: 4.799
Authors: Stefan Puchner; Doreen Schmidl; Laurin Ginner; Marco Augustin; Rainer Leitgeb; Stephan Szegedi; Kristina Stjepanek; Nikolaus Hommer; Martin Kallab; René Marcel Werkmeister; Leopold Schmetterer; Gerhard Garhofer Journal: Invest Ophthalmol Vis Sci Date: 2020-02-07 Impact factor: 4.799