Dynamic retinal vessel response to flicker in age-related macular degeneration patients before and after vascular endothelial growth factor inhibitor injection

Abstract

. Purpose: Retinal vessel responses to flickering light are different in various systemic and ocular diseases and can be improved after successful therapy. We investigated retinal vessel response to flickering light in age‐related macular degeneration (AMD) patients before and after treatment with a single intravitreal bevacizumab (Avastin®) injection. Methods: In 10 patients with exudative AMD [age: median (1.quartile; 3.quartile) 76.0 (73.5; 80.0) years], retinal vessel reactions were examined by Dynamic Vessel Analyser (DVA) before and 3 months after a single intravitreal application of bevacizumab (1.25 mg). A baseline measurement was followed by three consecutive monochromatic flicker stimulations (530–600 nm, 12.5 Hz, 20 seconds). Temporal retinal vessel reaction was analysed and compared with the reaction in healthy controls. Results: Mean arterial dilation at the end of flicker was not different in all groups. For veins this parameter amounted to: pre‐treatment, 2.6 (1.7; 3.9)%; post‐treatment, 2.9 (2.4; 4.0)%; control, 4.3 (3.2; 5.7)%; significant: pre‐treatment – control (Dunnett’s procedure, p < 0.05). Maximal dilation occurred in arteries at: pre‐treatment, 17.5 (14.8; 32.5) seconds; post‐treatment, 18.0 (16.6; 30.6) seconds; control, 14.5 (10.8; 17.3) seconds. Both AMD groups were slower (p < 0.05): in veins at 17.0 (14.5; 20.0) seconds, 12.8 (8.6; 14.8) seconds and 18.5 (17.1; 19.9) seconds, respectively; significant post‐treatment – control (p < 0.05). In the post‐treatment AMD group arterial constriction after stimulation occurred more slowly compared with the control group (p < 0.05). Conclusion: Dynamic retinal arterial and venous reactions to flickering light are altered in AMD compared with controls. Three months after a single injection of a vascular endothelial growth factor inhibitor, the investigated retinal dynamic vascular parameters were not altered in our study.

Flicker‐induced retinal vasodilatation is not dependent on complement factor H polymorphism in healthy young subjects

“…Whereas Sato and colleagues (Sato et al 2006) did not find a difference in mean blood velocity, arterial diameter or mean blood flow rate in patients with AMD, a more recent study demonstrates reduced blood flow velocities in patients with AMD compared with healthy subjects (Burgansky-Eliash et al 2014). Human studies investigating flicker-induced vasodilation in patients with AMD have also reported an altered flicker response in subjects with advanced AMD (Lanzl et al 2011). Whether these results can be attributed to vascular dysregulation leading to a decreased sensitivity of the retina to the flicker stimulus or to neuronal dysfunction remains unclear.…”

“…A recent study, however, reports that retinal blood flow velocities are reduced in patients with AMD (Burgansky-Eliash et al 2014). In addition, it has been shown that flickering light-induced vasodilation of retinal vessels is altered in patients with advanced AMD (Lanzl et al 2011). Based on these findings, one might hypothesize that also retinal blood flow regulation may be compromised in patients with AMD.…”

Flicker‐induced retinal vasodilatation is not dependent on complement factor H polymorphism in healthy young subjects

“…Whereas Sato and colleagues (Sato et al 2006) did not find a difference in mean blood velocity, arterial diameter or mean blood flow rate in patients with AMD, a more recent study demonstrates reduced blood flow velocities in patients with AMD compared with healthy subjects (Burgansky-Eliash et al 2014). Human studies investigating flicker-induced vasodilation in patients with AMD have also reported an altered flicker response in subjects with advanced AMD (Lanzl et al 2011). Whether these results can be attributed to vascular dysregulation leading to a decreased sensitivity of the retina to the flicker stimulus or to neuronal dysfunction remains unclear.…”

“…A recent study, however, reports that retinal blood flow velocities are reduced in patients with AMD (Burgansky-Eliash et al 2014). In addition, it has been shown that flickering light-induced vasodilation of retinal vessels is altered in patients with advanced AMD (Lanzl et al 2011). Based on these findings, one might hypothesize that also retinal blood flow regulation may be compromised in patients with AMD.…”

Retinal vessel diameter can reliably be determined in minipigs using Retinal Vessel Analyser with a microscope‐mounted fundus camera

“…Retinal vessel response to drugs already used in ophthalmology has recently begun to draw interest (Papadopoulou et al. 2009; Lanzl et al. 2011).…”