Dynamic retinal vessel reaction in patients with primary open angle glaucoma

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 stimulation (FLS) is investigated. Methods: Retinal vessel reactions to FLS 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 FLS (530-600 nm, 12,5 Hz, 20 s) was applied. Results: In most subjects fast vessel dilation compared to baseline and an ensuing reactive arterial constriction were observed. In detail we found: POAG.......control mean arterial dilation at the end of FLS, % 3,3±2,7......3,4±2,7 time of max arterial constriction following FLS,s....49,9±26,7*.25,5±18,1 mean venous dilation at the end of FLS,% 2,9±1,9......3,8±2,2 area under the venous curve following FLS,s*%..-1,1±16,9*...27,9±34,3 We 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 FLS does not differ between POAG patients and healthy subjects. Reactive arterial constriction following the FLS appeared later and venous restoration occurred faster in POAG. These findings might be an indication for alterations in the vascular endothelium and vessel wall rigidity in POAG, leading to impaired regulation following metabolic demand.