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Complex regulation of choroidal blood flow during combined changes in blood pressure and IOP
Author(s) -
SCHMETTERER L
Publication year - 2009
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2009.4411.x
Subject(s) - choroid , medicine , intraocular pressure , ophthalmology , blood flow , blood pressure , perfusion , correlation , cardiology , mathematics , biology , retina , neuroscience , geometry
Purpose In the recent years it has been shown that the human choroid shows some regulatory capacity during an artifical increase in intraocular pressure (IOP) as well as during an exercise induced increase in mean arterial pressure (MAP). The purpose of the present study was to test the hypothesis that human choroidal blood flow (ChBF) may depend, not only on ocular perfusion pressure (OPP), but also on absolute levels of MAP and IOP. Methods In a clinical study in 28 helathy subjects OPP was varied by elevating IOP during a squatting‐induced increase in MAP. IOP was raised in stepwise increments by using the suction cup method. Subfoveal choroidal blood flow (VhBF, laser Doppler flowmetry), MAP, and IOP were assessed, and OPP was calculated as (2/3)(MAP ‐ IOP). For correlation analysis, data from all subjects were pooled according to IOP and MAP values, and correlation analyses were performed. Results When data were grouped according to IOP, no correlation was observed between ChBF and MAP; but ChBFs were lower, the higher the IOP (P < 0.001). When data were grouped according to MAP, a significant correlation was found between ChBF and IOP (P < 0.001), but correlations were independent of MAP. Conclusion These data confirm previously published observations that the choroid shows some regulatory capacity during changes in OPP. In addition, the data indicate that the choroid regulates its blood flow better during exercise‐induced changes in MAP than during an experimental increase in IOP.