Retinal blood flow autoregulation after dynamic exercise in healthy young subjects

Purpose: To evaluate the retinal blood flow before and after the increase in systemic blood pressure to assess the autoregulation in healthy young subjects. Methods: Twenty eyes of 20 healthy volunteers were examined. The retinal blood flow was assessed by a Heidelberg retina flowmeter (HRF), while the systemic pressure was assessed by a portable electronic sphygmomanometer. Furthermore intraocular pressure (IOP) was always measured by a Goldmann tonometer immediately after HRF assessments. All measurements of physiological and flow parameters were performed with the subjects seated at rest and then immediately after stair climbing. Results: The IOP decreased significantly after dynamic exercise, while the heart rate and the systemic artery pressure increased significantly. At the baseline, the mean retinal blood flow was 276.8 \ub1 80.7 arbitrary units (AU) in the superotemporal area, 243.4 \ub1 63.68 AU in the superonasal area, 258.2 \ub1 67.37 AU in the inferotemporal area and 243.9 \ub1 72.24 AU in the inferonasal area. After dynamic exercise the mean retinal blood flow was 249.8 \ub1 86.78 AU in the superotemporal area, 248.7 \ub1 63.87 AU in the superonasal area, 245.4 \ub1 83.85 AU in the inferotemporal area and 228.8 \ub1 62.53 AU in the inferonasal area. No significant change in retinal blood flow was found. Conclusion: Our data support the hypothesis that in normal subjects autoregulation is sufficient to compensate the increase in blood pressure and maintain a stable retinal blood flow after exercise. Copyright \ua9 2007 S. Karger AG