Aim: We compared the regulatory responses induced by isometric exercise in control subjects and patients with age-related macular degeneration (AMD) to investigate choroidal vascular regulation in AMD.
Methods: Seventeen eyes of 17 patients with dry AMD in the study eye and 19 eyes of 19 controls were included in this study. Both groups were well matched for age, race and sex. 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 s of baseline, and then during 3 min of isometric exercise consisting of squeezing a handgrip in each hand. Similar measurements were then also obtained during the 2 min 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 control subjects. The slope for the relationship between circulatory changes and perfusion pressure changes was calculated and compared between patients with AMD and controls using linear regression analysis. Analysis of data was performed in a masked fashion.
Results: There were no statistically significant differences between the changes in choroidal blood velocity, volume and flow observed in control subjects and patients with AMD during the isometric exercise phase and after exercise.
Conclusions: Our results suggest that the response of the choroidal circulation to this type of isometric exercise resulting in a moderate increase in blood pressure does not seem to be affected by AMD.