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T. I. Metelitsina, J. E. Grunwald, J. C. DuPont, G.-S. Ying; Effect of Isometric Exercise on Choroidal Blood Flow in Patients With Age-Related Macular Degeneration (AMD). Invest. Ophthalmol. Vis. Sci. 2008;49(13):2240.
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To investigate the choroidal vascular regulation in AMD we compared the regulatory responses induced by isometric exercise in normal subjects and patients with AMD.
Seventeen eyes of 17 patients with dry AMD in the study eye and 19 eyes of 19 normal controls were included in this study. Both groups were well matched in regards to age, race and gender. Brachial artery blood pressure determinations and laser Doppler flowmetry (Oculix) measurements of relative foveolar choroidal blood velocity, volume, and flow were obtained in the study eye of each subject during 30 seconds of baseline, and then, during 3 minutes of isometric exercise consisting of squeezing a hand grip in each hand. Similar measurements were then also obtained during the two minutes following the cessation of exercise. Using non-paired, two-tailed t-test, changes in circulatory parameters during exercise and following the end of exercise were compared between AMD patients and normal subjects. The slope of the relationship between circulatory changes and perfusion pressure changes was assessed for each subject by regression analysis. Analysis of data was performed in a masked fashion. Circulatory measurements are shown in arbitrary units (AU), as mean ± 1 SD.
Analysis of the data showed no statistically significant differences between the changes in ChBVel, ChBVol and ChBFlow observed in normal subjects and AMD patients during exercise. After cessation of exercise a significant difference in the slopes of the relationship between perfusion pressure and velocity (P value = 0.007) and perfusion pressure and volume (P value = 0.04) were observed between AMD patients and normal subjects.
Our results suggest that the response of the choroidal circulation to this type of isometric exercise does not seem to be affected by AMD. Although blood flow changes are not significantly different after cessation of exercise, there are significant differences in the relationship betweenperfusion pressure and Velocity or Volume that need to be further investigated.
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