Purpose
As a sign of autoregulation retinal arterioles and venoles dilate in response to flicker stimulation. This response can be attributed to vascular endothelial function. It has been shown that in coronary arteries the endothelial-dependent vasomotion improves significantly after flavonoid-rich dark chocolate. Aim of the present study was to investigate whether dark chocolate leads to an improvement of retinal endothelial function in glaucoma patients and age-matched healthy subjects using the Dynamic Vessel Analyzer (DVA,Imedos, Jena, Germany).
Methods
Subjects: Patients with primary open-angle glaucoma (GL) n=18; m/f=5/13, control subjects (CS) n=18 m/f=7/1; Age GL: 65±6 (arithmet mean±s, years); CS: 64±7 (p=0.72). RR prior DVA: GL141/82±18/9 mmHg; CS: 133/79±14/11 (p=0.17/0.22). Visual field: GL: Mean defect: -17.9,-2.1,2.7 db (Minimum, median, maximum); PSD: 1.1, 2.4, 15.6. The patients and controls were assigned to dark or white chocolate (C) by randomisation with forced equal distribution. The number in each of the four groups was 9. Examination: Following pupil dilation measurement of blood pressure, intraocular pressure, blood glucose was done followed by DVA. This instrument consists of a fundus camera, video equipment and computer-aided process control. Recording procedure: Online measurement of the diameter of a retinal arteriolar and a venolar vessel segment, 50s baseline, three periods of 20s flicker stimulation and 80s follow- up registration. Three registrations were averaged. The change of the vessel diameter following flicker stimulation before and 2 hours after chocolate ingestion was measured. Statistics: Eight paired Wilcoxon tests with Bonferroni-Holm correction. H0: Vessel dilation (DIL)before=DILafter. H1:DILafter>DILbefore. One sided 5% sigificance level p=0.1.
Results
GL: DIL of arterioles before and after comsuption of darkC or whiteC didn't differ. Lowest p=0.41. CS: DIL of the arterioles didn't differ significantly. Lowest p=0.56. DIL of venules before darkC =1.9, 3.1, 4.4; after darkC=1.9, 5.2, 6.9; p=0.08. DIL of veins before whiteC=2.4, 2.8, 5.6; after whiteC=1.4, 3.0, 5.8; p=0.95.
Conclusions
In GL patients retinal vessel autoregulation remained unchanged by darkC or whiteC. In our control subjects, however, the extent of the autoregulatory response to flicker stimulation improved statistically significantly by darkC but not by whiteC which contains no flavonoids.
Keywords: 617 nitric oxide •
550 imaging/image analysis: clinical