Characterization of laser speckle flowgraphy pulse waveform parameters for the evaluation of the optic nerve head and retinal circulation

Abstract

To characterize laser speckle flowgraphy (LSFG) pulse waveform parameters for ocular circulation evaluation, a multicenter, prospective, cross-sectional study was conducted in 111 eyes of 86 healthy Japanese individuals. Optic nerve head (ONH) tissue-area, vessel-area mean blur rate (MT and MV, respectively), and MT and MV pulse waveform parameters were obtained using LSFG and ONH structural parameters using planimetry. Multivariate linear mixed-effects modeled regression analysis identified factors contributing to MT- or MV-waveforms using age, gender, smoking history, body mass index, systolic and diastolic blood pressure, heart rate, intraocular pressure, axial length, disc, rim, and β-peripapillary atrophy areas, MT or MV, central retinal artery, and vein equivalents (CRAE and CRVE) as explanatory variables. MT- and MV-waveforms significantly correlated with one or more systemic factors, consistent with previous studies. Following confounding factor adjustment, MT-Skew significantly negatively correlated with β-PPA area (P = 0.026); MT- and MV-flow acceleration index positively correlated with CRAE, MT, and MV (P = 0.041–< 0.001), compatible with these parameters’ observed correlations to systemic factors. Significantly negative correlations of the blowout score and acceleration time index to CRAE partly conflicted with their correlations to systemic factors, and other waveform parameters showed little correlation to ocular factors. Thus, Skew and flow acceleration index assisted the in vivo ocular circulation characterization.

Sex differences in the association between systemic oxidative stress status and optic nerve head blood flow in normal-tension glaucoma

“…Disc area was also associated with MBR-T in both sexes and in the group overall (overall, β = -0.16, p = 0.003; male, β = -0.21, p = 0.021; female, β = -0.15, p = 0.028). This finding is compatible with a previous study conducted with healthy subjects [25]. Although IOP was associated with MBR-T in the overall…”

“…As already mentioned, it has been suggested that MBR-T is a good indicator of structural and functional changes in glaucoma [13,33]. FAI-T is an indicator of the instantaneous force that can increase OBF in a short time [25]. A case-control study of patients with European ancestry has shown that NTG patients have lower FAI-T (i.e., a flattened pulse waveform) than healthy subjects [52].…”

“…Pulse-waveform parameters were also measured with LSFG in the tissue area of the ONH, including flow acceleration index (FAI-T), blowout score (BOS-T), and blowout time (BOT-T). FAI-T indicates the instantaneous force with which blood flow increases in a short time; it is calculated as the maximum change among all frames (1/30 s) in a rising curve [25]. BOS-T is an indicator of the volume of blood flow maintained in a vessel between heartbeats [26].…”

Multimodal imaging of the optic nerve head in retinitis pigmentosa

“…In this study we investigated the change of blood ow to the MV and MT. The MV re ects blood ow in the major retinal vessels supplied by the central retinal artery and vein, while the MT re ects blood ow in the ONH peripheral circulation supplied by the short posterior ciliary artery and vein [20]. We found that both MT and MV were decreased, compared to past reports of normal subject data with similar average age [21,22].…”

Longitudinal Study of Optic Disk Perfusion and Retinal Structure in Leber's Hereditary Optic Neuropathy

“…The LSFG disk area, as measured in pixels, showed moderate to strong correlation with the disk area, as measured on magnification-corrected pictures taken by fundus camera in healthy Japanese subjects. 26 …”