Impact of the Valsalva manoeuvre on the choroid: A systematic review with meta-analyses.

A variety of daily activities can intentionally or unintentionally cause the Valsalva manoeuvre, which induces a physiological response of elevated peripheral venous pressure. Studies have speculated that it may ultimately affect the choroidal anatomy. This is particularly important from a clinical point-of-view since patients occasionally hold their breath while undergoing macular optical coherence tomography (OCT). In this study, we systematically reviewed the literature to understand the impact of the Valsalva manoeuvre on the choroid and conducted meta-analyses on the changes induced in the subfoveal choroidal thickness (SFCT) and the choroidal vascularity index (CVI). We searched 12 literature databases for studies in healthy participants undergoing Valsalva manoeuvre with choroidal OCT scans before and during the manoeuvre. Seven studies with a total of 444 eyes of 279 individuals were eligible for the review. The Valsalva manoeuvre led to a statistically significant but numerically small increase in the SFCT of 6.5 μm (95% CI: 1.6-11.4 μm; p = 0.01) and a statistically significant increase in the CVI of 1.48 (95% CI: 1.23-1.73; p = 0.0002). Thus, the Valsalva manoeuvre has a measurable impact on the choroid, and we recommend careful observation of how the patient sits and behaves behind the OCT scanner while scanning in order to allow accurate measurements of the choroid for diagnosis and monitoring.