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Assessment of choroidal blood flow using laser speckle flowgraphy
  1. Giacomo Calzetti1,2,
  2. Klemens Fondi1,
  3. Ahmed M Bata1,
  4. Nikolaus Luft3,4,
  5. Piotr A Wozniak1,5,
  6. Katarzyna J Witkowska1,
  7. Matthias Bolz3,
  8. Alina Popa-Cherecheanu6,7,
  9. René M Werkmeister8,
  10. Doreen Schmidl1,
  11. Gerhard Garhöfer1,
  12. Leopold Schmetterer1,8,9,10,11
  1. 1 Department of Clinical Pharmacology, Medical University of Vienna, Vienna, Austria
  2. 2 Department of Ophthalmology, University of Parma, Parma, Italy
  3. 3 Department of Ophthalmology, Kepler University Hospital, Linz, Austria
  4. 4 Center for Refractive Therapy, University Eye Hospital, Ludwig-Maximilians-University, Munich, Germany
  5. 5 Department of Ophthalmology, Medical University of Warsaw, Warsaw, Poland
  6. 6 Carol Davila University of Medicine and Pharmacy, Bucharest, Romania
  7. 7 Department of Ophthalmology, Emergency University Hospital, Bucharest, Romania
  8. 8 Center for Medical Physics and Biomedical Engineering, Medical University of Vienna, Vienna, Austria
  9. 9 Singapore Eye Research Institute, Singapore
  10. 10 Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
  11. 11 Ophthalmology and Visual Sciences Academic Clinical Program, Duke-NUS Medical School, Singapore
  1. Correspondence to Professor Leopold Schmetterer, Department of Clinical Pharmacology, Medical University of Vienna, Vienna 1090, Austria; leopold.schmetterer{at}meduniwien.ac.at

Abstract

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.

  • imaging
  • choroid
  • physiology

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Footnotes

  • 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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