Laser doppler holography for choroidal blood flow assessment: a systematic review of technical capabilities, validation studies, and clinical applications

Introduction: Quantitative choroidal blood flow assessment is important for understanding chorioretinal diseases. Laser Doppler Holography (LDH) is a new non-invasive imaging technique that provides full-field, high-temporal-resolution assessments of ocular hemodynamics. This systematic review synthesizes evidence on LDH’s technical capabilities, clinical applications, and provides normative reference values for choroidal vascular anatomy. Methods: A systematic search of the literature was undertaken in accordance with PRISMA guidelines. Studies that evaluated choroidal blood flow in humans using LDH were identified. Data on technical specifications, hemodynamic parameters, and vascular anatomy were extracted for narrative synthesis. Results: The comprehensive literature search resulted in 347 records, with 8 studies that met the inclusion criteria for qualitative synthesis, as well as 2 studies that could be included in the meta-analysis. The pooled mean diameter of the choroidal arteries was derived to be 134.2 mm (95% CI: 128.3 to 140.1 mm) based on the meta-analysis and demonstrated low levels of heterogeneity (I2 = 0). Discussion: The narrative synthesis found that LDH could assess choroidal vasculature, differentiate arteries from veins using both flow waveforms and spectral data, deliver quantitative data for hemodynamic parameters, and assess blood flow directionality. LDH is a promising and versatile technique to study choroidal blood flow quickly and non-invasively.