Estimation of Time Delay Between Artery and Vein Pulsation using Experimental Video-Ophthalmoscope

The fundus observation by ophthalmoscope is a non-invasive approach for diagnosis of various retinal diseases. The vein and artery pulsation are usually clearly apparent on fundus and might be also important for medical practice. Thus our method focuses on these changes and analyzes the time delay between the pulsation signal detected in the vein and the artery region. Data acquired by an experimental video-ophthalmoscope from five subjects with no eye diseases are analyzed. The analysis is based on the selection of artery and vein regions of interest and computation of averaged brightness within these regions for each frame. These extracted signals are filtered, interpolated and the trend is eliminated. Finally, the delays between artery and vein pulsation signals are determined using phase spectra. The measured delays are in the range of 15 to 95 ms, which is comparable with other published results.