High speed in-vivo imaging of retinal hemodynamics in a rodent model of hypertension.

The eye is the only organ through which microcirculation can be visualized non-invasively. This unique feature makes the eye and specifically retinal vasculature an excellent target area to monitor and study micro-vascular damage in systemic diseases. Dynamic (real-time) changes of retinal vessels have been shown to be more specific to the disease in comparison with static measurements. In this study we utilize high speed imaging (i.e. 125 fps) to study and derive dynamic changes of retinal vessels in a rat model of hypertension. A Eulerian video magnification algorithm was used to extract retinal arterial and venous pulse amplitude from five Spontaneously Hypertensive Rats (SHR) and five Wister Kyoto (WKY) rats were used as the control group. Results showed that retinal arterial diameter and pulse amplitude are significantly lower in the SHRs compared with WKYs. Dynamic biomarkers of retinal micro-vasculature may be used as a diagnostic tool for systemic diseases.