Ocular Blood Velocity Measurement With Optical Coherence Tomography Using Speckle Analysis

To develop and validate a novel method for quantifying blood flow velocity in ocular vessels using speckle pattern analysis in optical coherence tomography (OCT) images.

We developed an OCT-based methodology that quantifies flow velocity by analyzing speckle structures within OCT images to derive a relative flow value (RFV) based on the horizontal derivative of speckle patterns. A model eye with 150-µm capillary tubing was used to evaluate speckle pattern analysis at controlled flow rates of human and porcine blood. We assessed the correlation between RFV and actual flow velocities and examined measurement consistency across vessel sectioning angles varying ±20° from perpendicular.

RFV exhibited a power-law relationship with actual flow velocities, RFV = 169.6 × (Actual Flow)0.264 (r2 = 0.983), and maintained accuracy without saturation up to 70 mm/s. Measurements remained consistent across vessel sectioning angles. Intraluminal speckle structures changed dynamically with flow velocity, and averaged images revealed characteristic hourglass profiles at higher velocities. In a patient with central retinal vein occlusion, RFV detected altered pulsatility and reduced venous flow, aligning with clinical expectations.

This speckle-based OCT method provides a non-invasive, depth-resolved approach for quantifying ocular blood velocity with minimal computational requirements. It holds potential for diagnosing and monitoring vascular abnormalities in ocular and systemic diseases. Further validation is necessary across diverse patient populations.

This method simplifies blood flow quantification, enhancing the role of OCT in hemodynamic assessment both ocularly and systemically.