Reliability of confocal choroidal laser Doppler flowmetry.

Area of Science:

• Ophthalmology
• Biomedical Optics
• Physiology

Background:

• Choroidal blood flow is crucial for ocular health.
• Laser Doppler flowmetry (LDF) is used to measure choroidal blood flow.
• Variability in LDF measurements can limit its clinical utility.

Purpose of the Study:

• To assess the variability in choroidal laser Doppler flowmetry (LDF).
• To investigate the influence of signal yield and tissue scattering properties on LDF measurements.
• To improve the reliability and reproducibility of choroidal LDF.

Main Methods:

• Obtained five measurements of choroidal blood flow in both eyes of 10 subjects over 5 days.
• Calculated signal yield (DC/gain) and analyzed its correlation with LDF parameters (velocity, volume, flux).
• Performed reliability, sensitivity, and sample size calculations before and after correcting for yield, and assessed light-scattering effects in a model eye.

Main Results:

• Signal yield significantly correlated with LDF parameters (velocity, volume, flux).
• Correcting for yield markedly improved reliability, reproducibility, sensitivity, and statistical power.
• High reliability of yield (87%) suggests individual scattering properties influence LDF.
• Low signal-to-noise ratio observed with decreasing yield in model and human eyes.

Conclusions:

• Tissue-scattering properties and recording settings affect choroidal LDF outcomes.
• Partializing out the influence of signal yield significantly enhances the reproducibility of choroidal LDF.
• This correction method improves the accuracy and reliability of choroidal blood flow measurements.