Intraday and Interday Repeatability of Laser Speckle Contrast Imaging for Ocular Blood Flow Measurement in Healthy Subjects

Purpose: To investigate the intra- and interday repeatability of ocular blood flow velocity index (BFVi) measurements using a laser speckle contrast imaging device. Methods: BFVi measurements were obtained using XyCAM CRE (Vasoptic Medical Inc., Columbia, MD). Two imaging sessions were performed on the same day (26 eyes) and on different days (20 eyes). For optic nerve head-centered datasets, the analyzed regions included the overall field of view, the optic disc, and a standard temporal peripapillary region. For macula-centered datasets, the regions analyzed were the overall field of view, the foveal avascular zone, and the perifoveal region. For each region, heart rate-adjusted measurements of the peak, dip, and mean BFVi were assessed. Results: For intraday measurements of all the optic nerve head-centered parameters, the coefficients of variation (CVs) ranged from 4.8% to 8.5%, and the intraclass correlation coefficient ranged from 0.74 to 0.98. For all macula-centered parameters, the CVs ranged from 4.7% to 6.2%, and the ICCs ranged from 0.93 to 0.98. For the interday measurements of all the optic nerve head-centered parameters, the CVs ranged from 7.9% to 12.6%, and the ICCs ranged from 0.56 to 0.93. For all the macula-centered parameters, the CVs ranged from 8.6% to 15.0%, and the intraclass correlation coefficient ranged from 0.79 to 0.94. Conclusions: Laser speckle contrast imaging demonstrated strong intraday repeatability and reliability for BFVi measurement in healthy subjects, with good interday reliability for key parameters despite some variability. Translational Relevance: Laser speckle contrast imaging shows promise for clinical use in ophthalmology due to its robust intraday and good interday reliability for ocular blood flow velocity measurements.