Autoregulation of retinal arterioles in diabetics and normal subjects

Background: Measurement of myogenic autoregulation of retinal arterioles was demonstrated by the use of the Retinal-Vessel-Analyzer (Carl Zeiss, Jena). The purpose of the presented study was to find a significant difference of this myogenic response in a group of healthy individuals vs, a group of patients with pathologic conditions. Patients and methods: As a group of patients with known pathology in microcirculation patients with type 1 diabetes were choosen. By isometric exercise an identical rise in mean arterial blood-pressure was provoked in 20 patients with type-1 diabetes and 20 matched healthy volunteers. The myogenic response of retinal arterioles was measured in both groups by the use of the Retina l-Vessel-Analyzer. The Wilcoxon test was used for statistical analysis within the two groups whereas both groups were compared with each other by the use of the Mann-Whitney test. Results: Having the same age and same blood-pressure rise (p = 0.624) a significant better myogenic response was found in the healthy subjects vs. the diabetic group (p = 0.008). In the diabetec group no correlation was found between myogenic response and duration of diabetes (p = 0.982) or HbA1c values (P = 0.83). Conclusions: In this study significant loss of autoregulation in patients with type 1 diabetes is demonstrated. By the use of the Retinal-Vessel-Analyzer noninvasive testing of the function of autoregulation of retinal arterioles is possible. This method might prove to be of great value in early detection of diabetic vessel pathology.