Abstract
Purpose: :
Impaired vascular regulation might contribute to glaucomatous damage. Whether retinal branch arteries and veins of healthy persons and primary open angle glaucoma (POAG) patients show different reactions in response to flickering light is investigated.
Methods: :
Retinal vessel reactions to flicker stimulation were examined in 28 POAG patients (stage I, 54,3±9,9 years old) after 4 week wash-out of eye drops and in 28 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.
Results: :
In most subjects fast vessel dilation compared to baseline and an ensuing reactive arterial constriction were observed. In detail we found:…………………………………...….POAG……..controlmean arterial dilationat the end of stimulation, [%]....…3,3±2,7.........3,4±2,7time of max. arterial constrictionfollowing the stimulation, [s]..…...49,9±26,7**..25,5±18,1mean venous dilationat the end of stimulation, [%]……2,9±1,9.........3,8±2,2area under the venous curvefollowing the stimulation, [s*%]...-1,1±16,9**.…27,9±34,3We found statistically significant differences between the two examined groups as marked with **(p<0,01) (U-test).
Conclusions: :
Functional retinal arterial and venous dilation in response to flicker stimulation does not differ between POAG patients and healthy subjects. Reactive arterial constriction following the stimulation appeared later and venous restoration occurred faster in POAG. These findings in the time course of vessel reaction in POAG might be an indication for alterations in the vascular endothelium and vessel wall rigidity in glaucoma, leading to impaired regulation following metabolic demand.
Keywords: retina • blood supply • optic flow