Empirical retinal venous pulse wave velocity using modified photoplethysmography

Area of Science:

• Ophthalmology
• Biomedical Engineering
• Medical Imaging

Background:

• Retinal venous pulse wave velocity is a critical hemodynamic parameter.
• Accurate measurement of this parameter is essential for understanding ocular blood flow.
• Novel imaging techniques are needed to non-invasively assess retinal hemodynamics.

Purpose of the Study:

• To measure retinal venous pulse wave velocity using a novel high-speed modified photoplethysmography technique.
• To characterize the dynamic wall motion of retinal veins during pulsation.
• To establish a baseline measurement for future research in this area.

Main Methods:

• High-speed modified photoplethysmography (120 frames per second) was employed.
• Simultaneous ophthalmodynamometry was performed.
• Custom software analyzed optic nerve videos, fitting a harmonic regression model to quantify vascular pulse wave parameters.

Main Results:

• Retinal venous pulsation was observed as complex dynamic wall motion at the optic disc.
• Contraction initiated centrally and progressed centrifugally.
• The estimated retinal venous pulse wave velocity was approximately 22.25 mm/s.

Conclusions:

• High-speed modified photoplethysmography can visualize and quantify retinal venous pulsation.
• This study provides an initial estimate of retinal venous pulse wave velocity.
• The findings support the potential of this technique for future hemodynamic studies in the eye.