Effect of Glucose on Ocular Blood Flow

Overview

The primary objective is to assess the effect of glucose on retinal vascular diameter in otherwise healthy vasospastic subjects compared to non-vasospastic controls. The secondary objective is to compare the effect of glucose also on choroidal blood flow in otherwise healthy vasospastic subjects with non-vasospastic controls.

It is known that a glucose load can induce an increase in ocular blood flow. Acute hyperglycemia increases retinal vessel diameters in animals and humans. The purpose of this study is to compare the effect of glucose on the ocular blood flow in vasospastics and nonvasospastics. Body core temperature depends on basal metabolism. Peripheral vasoconstriction is a physiological way to preserve core temperature of the body. The etiology of primary vasospastic syndrome is unknown and potentially represents simply a reaction to a defective metabolism. Based on this hypothesis, vasospastics are expected to show a different vascular reaction to glucose. On both study days, after an overnight fast, the subjects will be seated for 30 minutes in the Lab and local tropicamide will be applied for pupil dilatation. After stabilisation of blood pressure Retinal vessel diameter and choroidal blood flow will be assessed. Baseline blood glucose levels will be measured. Afterwards study substance (75 gram of Glucose or Aspartate) will be applied in 3 dl of water. One and a half hour later, the vascular measurements will be repeated. Ath the end of hemodynamic assessments, blood sugar level will be measured again.

Conditions

Eligibility

Locations (1)