Background/aims There is considerable interest in novel techniques to quantify choroidal blood flow (CBF) in humans. In the present study, we investigated a novel technique to measure CBF based on laser speckle flowgraphy (LSFG) in healthy subjects.
Methods This study included 31 eyes of 31 healthy, non-smoking subjects aged between 19 and 74 years. A commercial LSFG instrument was used to measure choroidal vessel diameter (CVD) and relative flow volume (RFV) in choroidal vessels that were identified on fundus photos, an approach that was used previously only for retinal vessels. The reproducibility and the effect of isometric exercise on these parameters were investigated. The latter was compared with measurement of subfoveal CBF using laser Doppler flowmetry (LDF).
Results Intraclass correlation coefficients for CVD and RFV were higher than 0.8 indicating excellent reproducibility. During isometric exercise, we observed an increase in ocular perfusion pressure of approximately 60% (P<0.001). The increase in RFV and CBF was lower, but also highly significant versus baseline (at minute 6 of isometric exercise: RFV 10.5%±4.2%, CBF 8.3%±3.6%; P<0.001 each) indicating choroidal autoregulation.
Conclusion LSFG may be a novel approach to study blood flow in choroidal vessels. Data are reproducible and show good agreement with LDF data.
Trial registration number NCT02102880, Results.
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Contributors GC: conceptualisation, formal analysis, investigation, methodology, visualisation, writing the original draft. KF, AMB, NL and PAW: formal analysis, methodology and investigation. KJW: investigation and project administration. MB: funding acquisition and methodology. AP-C: conceptualisation and project administration. RMW: conceptualisation, formal analysis, investigation, methodology and supervision. DS: conceptualisation, formal analysis, investigation and methodology. GG: conceptualisation, formal analysis, investigation, methodology, supervision, validation and visualisation. LS: conceptualisation, formal analysis, funding acquisition, methodology, project administration, supervision, validation, visualisation and writing the original draft. All authors contributed to writing, reviewing and editing the final manuscript.
Funding Financial support from the Austrian Science Fund (Fonds zur Förderung der Wissenschaftlichen Forschung; www.fwf.ac.at) Grant 21406 and project KLI 340 is gratefully acknowledged.
Competing interests None declared.
Patient consent Obtained.
Ethics approval Ethics Committee of the Medical University of Vienna.
Provenance and peer review Not commissioned; externally peer reviewed.
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