Abstract
Purpose: :
Exposure of the retina to flickering light induces retinal vessel dilation in healthy subjects. The effect is termed neurovascular coupling. Vessel responses are assumed to be different in various diseases. Whether the dynamic reaction to luminance flicker stimulation in retinal branch arteries and veins differs between healthy volunteers and patients suffering from obesity is investigated.
Methods: :
Retinal vessel reactions to flicker stimulation were examined in 46 patients with obesity (age (mean±SD) 49,6 ± 10 years old) and in 46 age and gender matched medically healthy volunteers. Vessel diameters of retinal vessel segments were assessed by Dynamic Vessel Analyzer (DVA). After baseline measurement (50 s) monochromatic rectangular flicker stimulation (530-600 nm, 12,5 Hz, 20 s) was applied 3 consecutive times. Statistical data analysis of the measured parameters independent from the commercial DVA program was performed.
Results: :
In most subjects fast vessel dilation compared to baseline and an ensuing reactive arterial constriction were observed. In detail we found:...............................................................obesity ..... controlmean maximal arterial dilation, [%]: ........3,2±1,8*..... 4,1±2,0time of max. arterial dilation during the stimulation, [s]:.. 18,0±9,4*.....14,6±3,8mean maximal venous dilation, [%]: .....4,0±1,7* .....4,7±1,8There were statistically significant differences between the two examined groups as marked with *(p<0,05).
Conclusions: :
Functional retinal arterial and venous reaction to flicker stimulation differs significantly between obese patients and healthy subjects of the same age and gender. These functional retinal vessel abnormalities in obesity are similar to vascular changes found with increased age, diabetic and hypertensive patients.
Keywords: blood supply • brightness and lightness • retina