Abstract
Purpose: :
To evaluate the influence of the duration of flicker-light provocation on retinal vessel dilation.
Methods: :
Twelve healthy individuals (mean age 32 +/-7 yrs) underwent continuous retinal vessel diameter measurement of both arterioles and venules using the DVA (Dynamic Retinal Vessel Analyser; Imedos Systems, Germany). Each subject underwent four measurement protocols, in a random order, comprising 50s baseline measurement followed by 3 cycles each of 5, 7, 10 or 20s flicker-light stimulation and 80s recovery (total duration: 305-350s).
Results: :
A stepwise forward regression analysis revealed no influence of age, vessel diameter, blood or intra ocular pressure on retinal arteriolar or venular dilation due to flicker provocation. Retinal vessel diameter changes (maximum dilation, maximum constriction and dilation amplitude) due to flicker-light provocation were independent of flicker duration for arteries (F(3,43)=0.7, p=0.571) and veins (F(3,43)=2.5, p=0.075).
Conclusions: :
Shorter stimulation protocols may be sufficient to evaluate vessel function. In addition, shorter protocols are also more suitable for those with fixation problems.
Keywords: retina • imaging/image analysis: clinical • discrimination