Abstract
Purpose :
There are limited methods to quantify the retinal vascular pulse wave parameters. We describe a novel, non-invasive technique to objectively quantify the retinal vascular pulse wave Fourier amplitude in in a group of normal subjects
Methods :
Sixteen patients (27 eyes) underwent modified retinal photo-plethysmography. Analysis of pulsatility timed to the cardiac cycle generated pulsation amplitude values calculated using Fourier analysis. A generalized linear mixed effects model was used to analyse the correlations of both the composite Fourier amplitude and individual cosine (an1,2) and sine (bn1,2) coefficients of the first two harmonics with both distance along the vessel and ophthalmodynamometric force (ODF)
Results :
A total of 36,619 data points were sampled (16,977 arterial and 19,642 venous). The median Fourier amplitude in the venous system was 5.11 (range= 0.16 - 56.6), compared to the arterial system 3.36 (range = 0.20 - 28.54).
There was a decay of the logarithmically transformed Fourier amplitude as a function of distance from the center of the optic disc to the periphery of -0.4±0.065 in the venous system as opposed to -0.17±0.048 in the arterial system. In contrast there was a direct correlation between Fourier amplitude with ODF in both the venous system (coefficient value = 0.0033±0.0015, p=0.04) and in the arterial system where the coefficient failed to achieve statistical significance (coefficient value = 0.0014±0.001, p=0.3)
Interaction of distance along the vessel and ODF showed that there was an increasing negative correlation of the logarithmically transformed Fourier amplitude with distance on increasing ODF in the venous system with steepening of the regression slope (-0.0018±0.004 p=0.0001). This correlation was sustained for the first and second harmonic coefficients with distance (p<0.0001-0.007) except for bn2 coefficient. In contrast only the an1 coefficient demonstrated a statistically significant positive correlation with ODF (p<0.01) for both retinal vascular systems
Conclusions :
Modified photo-plethysmography was used to analyse the retinal vascular pulse waveform using the Fourier series. Quantification of the retinal vascular pulse amplitude and describing its attenuation characteristics may have implications in distinguishing vascular parameters particularly vessel compliance
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.