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I. M. Lanzl, K. E. Kotliar, A. Bock, M. Halle, W. Vilser, A. Schmidt-Trucksaess; Age Dependence of Retinal Vessel Reaction to Flicker. Invest. Ophthalmol. Vis. Sci. 2007;48(13):2263.
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© ARVO (1962-2015); The Authors (2016-present)
Human retinal vessels and their reaction to stimuli change during life due to physiological, genetic and pathological influences. Using the Dynamic Vessel Analyzer (DVA, Fa. IMEDOS, Jena) it is possible to assess changes in retinal vessel diameters in response to vasoactive stimuli in real time and non-invasively. Luminance flicker stimulation was applied in the present study in order to investigate possible age related changes of the vessel diameter reaction in healthy volunteers.
Retinal arterial vessel reaction to the average of 3 consecutive monochromatic rectangular luminance flicker stimulations (wave lengths: 530-600 nm, frequency: 12,5 Hz, duration: 20 s) with a 80 s observation pause between stimulations was investigated in both eyes of 156 anamnestically healthy volunteers. 3 age groups were formed: young (52 persons, 29.1±5.2 years), middle age (54 persons, 44.5±4.3 years) and seniors (50 persons, 61.3±5.1 years). Included in the analysis were only volunteers without medical vascular risk factors defined as: blood pressure < 140/90 mmHg, HDL > 35 mg/dl, LDL < 190 mg/dl and glucose levels < 110 mg/dl. Statistical data analysis of vessel reactions independent from the DVA program was performed.
72 volunteers were not defined healthy by medical testing. One eye of the remaining 84 medically healthy volunteers was included in the analysis. A prompt retinal arterial and venous dilation in comparison to baseline was observed in all healthy volunteers. (p<0.001). Maximal vessel dilation at the end of flicker stimulation amounted to (arteries/veins): young: 3.3%±2.3% / 4.2%±1.9%, middle age: 3.8%±1,7% / 4.4%±2.2%, seniors: 2.6%±1.8% / 4.1%±1.7%. There was a statistically significant difference in arterial dilation between middle age and seniors (p<0.05). Mean maximal arterial constriction following the flicker stimulation amounted to: young: -2.6%±1.6%, middle age: -1.8%±1.4%, seniors: -1.4%±1.4%. There was a statistically significant difference in constriction between young persons and both older groups (p<0.05).
Flicker stimulation of the retina light evokes a prompt vessel reaction in all healthy subjects (neuro-vascular coupling). We could demonstrate an age dependence of the retinal arterial reaction in medically healthy persons. Application of flicker stimulus to retinal vessels may represent a method to assess the endothelial function of vessels.
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