Strategies for reducing variance in laser Doppler flowmetry measurements

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Physiology

Background:

• Laser Doppler flowmetry (LDF) in humans often suffers from data scattering.
• Variability in LDF data can be problematic for studies assessing choroidal blood flow.
• The total returning light level (DC) influences LDF parameters.

Purpose of the Study:

• To reduce variability in LDF data by eliminating the effect of the total returning light level (DC).
• To investigate two distinct methods for correcting LDF measurements in the choroid.

Main Methods:

• Measurements of choroidal blood flow parameters were taken in 20 healthy subjects using a portable confocal LDF device at varying DC values.
• Two strategies were employed to reduce data scattering by addressing the effect of yield (DC/gain): a third-order polynomial fit and a new linear fit method for individual subjects.

Main Results:

• Data variability was higher for LDF parameters volume and flow compared to velocity during DC changes.
• Both the polynomial fit and the linear fit methods demonstrated success in reducing LDF parameter scattering with varying DC.

Conclusions:

• Both tested methods effectively reduced LDF measurement variability by correcting for changes in yield.
• The presented approaches offer a potentially effective, applicable, and valid way to reduce data scattering in LDF assessments of posterior eye blood flow.
• Further research is needed to confirm the efficacy of these techniques when systematic DC changes occur post-intervention.