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Konstantin E Kotliar, Christine Hauser, Marion Ortner, Claudia Muggenthaler, Christoph Schmaderer, Arno Schmidt-Trucksaess, Ines Lanzl, Timo Grimmer; Does dynamic retinal vessel reaction to flickering light change in Alzheimer disease?. Invest. Ophthalmol. Vis. Sci. 2016;57(12):4623.
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© ARVO (1962-2015); The Authors (2016-present)
Retinal vessel response to flicker was shown to be altered in glaucoma, hypertension, diabetes mellitus and other ocular and systemic diseases. Vascular risk factors contribute significantly to the development of Alzheimer's disease (AD). Retinal vessels are similar to the brain vessels in their structure and function. Whether the dynamic regulative behavior of retinal vessels is changed in Alzheimer's disease and whether these changes are related to the severity of this disease is investigated.
Four groups of participants were recruited: 15 patients, 72.9 ± 9.0 years old with mild-to-moderate dementia due to probable AD fulfilling the standard diagnostic criteria; 24 patients, 68.2 ± 9.2 years old with mild cognitive impairment due to AD; 16 anamnestic healthy control subjects, 66.4 ± 7.6 years old without cognitive impairment as well as 10 medically validated healthy volunteers of similar age (64.2 ± 3.7 years old) and gender distribution. Retinal vessel reaction to flicker stimulation was examined by Dynamic Vessel Analyzer (DVA, IMEDOS Systems) in all the participants. After baseline assessment of 50 s monochromatic rectangular flicker stimulation (530-600 nm, 12.5 Hz, 20 s) was applied 3 consecutive times. Parameters of dynamic vascular response were analyzed independent from the commercial DVA software.
Both retinal arteries and veins in mild-to-moderate AD showed unexpectedly more emphasized reactive dilation in response to flicker in comparison to both control healthy groups. This tendency as compared to healthy control groups was shown also in the patients with mild cognitive impairment. Values of basic parameters of dynamic retinal vessel reaction in the examined groups and significance towards mild-to-moderate AD are presented in the table. [mean±std. deviation, t-test: *p<0.05; **p<0.001].
Functional vessel reaction to flicker stimulation changed significantly in mild-to-moderate AD: the magnitude of the vascular dilative response was unexpectedly enlarged. Further research of vascular dynamic function in AD should reveal the reason for upregulating behavior of retinal vessels in this disease. Since dynamic retinal vessel analysis provides a direct non-invasive assessment of microcirculatory damage, it could allow for additional diagnostic characterization of AD.
This is an abstract that was submitted for the 2016 ARVO Annual Meeting, held in Seattle, Wash., May 1-5, 2016.
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