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I.M. Lanzl, A. Wiescher, W. Vilser, K.E. Kotliar; Dynamic Retinal Vessel Response To Flicker In Migraine Patients . Invest. Ophthalmol. Vis. Sci. 2006;47(13):494.
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Exposure of the retina to flickering light induces retinal vessel dilation in healthy subjects. The effect is termed neurovascular coupling. Vessel responses are assumed to be different in various diseases. We investigated arterial vessel response to flicker light application in migraine patients.
In 21 neurologically confirmed migraine patients (age 21–64 (38,6±13,8) years), a retinal arterial vessel segment was examined by Retinal Vessel Analyzer (RVA). Characteristics of migraine were noted (presence of an aura, recurrence rate, duration of each migraine attack). A baseline measurement was performed for 1,5 min. Then a mixed chromatic flicker light alternating between the colors red – green and blue – green with a frequency of 2, 12, or 20 Hz and monochromatic green flicker light of 12,5 Hz was applied for 30 sec each. Subgroups of 10 patients each with the strongest and the least manifestation of a migraine attribute were formed. The results (area under the vessel reaction curve during the stimulation in sec*%) were compared by means of non–parametric statistics with previously obtained vessel reactions of age matched healthy volunteers.
In all patients an arterial vessel reaction in comparison to the baseline was found. Average reactions of the whole group do not differ significantly from the healthy group. The migraine patients were further divided into subgroups. No significant difference to the healthy group for the attribute "presence / absence of aura" was found (p>0,5). For the attribute "short/long duration" of migraine attack" and "rare/frequent migraine attack" a statistically significant difference of the flicker response between the corresponding subgroups was found (p<0,04). Specifically the arterial response in short duration and rare attack subgroups was of lesser magnitude and occurred temporally delayed.
The arterial vessel reaction in response to flicker light in our whole group of migraine patients does not differ from the reaction of the normal healthy group. In the subgroups formed according to migraine specific attributes a significant difference to the normal group was found for patient groups with a short duration and rare appearance of migraine attacks. We consider the observed effects to be a manifestation of the pathologic vessel regulation in migraine patients. Patients with more severe migraines might develop adaptation mechanisms, which could normalize their vessel reactions. The results of our study could add information to migraine research and also represent a basis for early migraine diagnosis.
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