Abstract
Purpose: :
The Retinal Function Imager (RFI) is a new, non-invasive diagnostic device measuring retinal blood flow velocity. Our aim is to study the relation between blood flow velocity to physiologic parameters in diabetic patients and healthy controls.
Methods: :
Thirty seven eyes of 27 patients with non-proliferative diabetic retinopathy (NPDR) and 24 eyes of 16 healthy controls were enrolled in this study. All patients were scanned 3 times on the same day with the RFI. The quantitative analysis of blood flow velocity and corresponding heart rate and blood pressure measurements were correlated using Pearson's correlation.
Results: :
The diabetic group exhibited a significantly faster heart rate than the healthy group (79.2 ± 11.6 vs 69.4 ± 6.4 beats/min, p<0.0001). There was no statistically significant difference between the mean arterial pressure in the diabetes and the healthy group. The heart rate of healthy subjects, displayed a positive correlation with the RFI-measured flow velocity both in the arteries (r2= 0.29, P = 0.007) as well as in the veins (r2 = 0.16, P = 0.05). Subsequently, only the arterial flow velocity of this group positively correlated with the mean arterial pressure (r2 = 0.29, P = 0.006; Fig. 3). There was no significant correlation between flow velocity and heart rate or mean arterial pressure in the diabetic group. Studying the individual heart rate recording in parallel with each velocity measurement, resulted in a correlation between blood-flow velocity and heart rate in diabetic patients, although the relationship was less pronounced than in the healthy subjects.
Conclusions: :
We found a difference in the correlation of blood flow velocity with heart rate and blood pressure between diabetic and healthy subjects. This finding is in consistent with the derangement of autoregulatory control mechanisms in diabetic patients and might be an important characteristic of diabetic retinopathy. The RFI provides a non-invasive technique to assess haemodynamic abnormalities in diabetic retinopathy and may assist in monitoring the disease and the effect of therapies.
Keywords: blood supply • diabetic retinopathy • imaging methods (CT, FA, ICG, MRI, OCT, RTA, SLO, ultrasound)