Inter-day repeatability assessment of human retinal blood flow using clinical laser speckle contrast imaging

Chen Qiu; Josephine Situ; Sheng-Ya Wang; Ehsan Vaghefi

doi:10.1364/BOE.468871

Inter-day repeatability assessment of human retinal blood flow using clinical laser speckle contrast imaging

Biomed Opt Express. 2022 Oct 31;13(11):6136-6152. doi: 10.1364/BOE.468871. eCollection 2022 Nov 1.

Authors

Chen Qiu^{1

2}, Josephine Situ³, Sheng-Ya Wang³, Ehsan Vaghefi^{4

5}

Affiliations

¹ Department of Physiology, School of Medical Sciences, University of Auckland, New Zealand.
² Department of Physics, University of Oxford, United Kingdom.
³ Department of Engineering Science, University of Auckland, New Zealand.
⁴ School of Optometry and Vision Science, University of Auckland, New Zealand.
⁵ Auckland Bioengineering Institute, University of Auckland, New Zealand.

Abstract

Laser speckle contrast imaging (LSCI) can generate retinal blood flow maps inexpensively and non-invasively. These flow maps can be used to identify various eye disorders associated with reduced blood flow. Despite early success, one of the major obstacles to clinical adoption of LSCI is poor repeatability of the modality. Here, we propose an LSCI registration pipeline that registers contrast maps to correct for rigid movements. Post-registration, intra(same)-day and inter(next)-day repeatability are studied using various quantitative metrics. We have studied LSCI repeatability intra-day by using the coefficient of variation. Using the processing pipelines and custom hardware developed, similar repeatability was observed when compared to previously reported values in the literature. Inter-day repeatability analysis indicates no statistical evidence (p = 0.09) of a difference between flow measurements performed on two independent days. Further improvements to hardware, environmental controls, and participant control must be made to provide higher confidence in the repeatability of blood flow. However, this is the first time that repeatability across two different days (inter-day) using multiple exposure speckle imaging (MESI) has been analyzed and reported.