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 ± 80.7 arbitrary units (AU) in the superotemporal area, 243.4 ± 63.68 AU in the superonasal area, 258.2 ± 67.37 AU in the inferotemporal area and 243.9 ± 72.24 AU in the inferonasal area. After dynamic exercise the mean retinal blood flow was 249.8 ± 86.78 AU in the superotemporal area, 248.7 ± 63.87 AU in the superonasal area, 245.4 ± 83.85 AU in the inferotemporal area and 228.8 ± 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 © 2007 S. Karger AG.