Retinal blood flow autoregulation after dynamic exercise in healthy young subjects.
OBJECTIVE
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.


CONCLUSIONS
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.
Iester
Michele
M
Department of Neurological Sciences, Ophthalmology and Genetics, Clinica Oculistica, University of Genoa, Genoa, Italy. iester@unige.it
Torre
Pier Giacomo
PG
Bricola
Graziano
G
Bagnis
Alessandro
A
Calabria
Giovanni
G
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D001794:Blood Pressure / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D012016:Reference Values; D012160:Retina / Q000502:physiology*; D012171:Retinal Vessels / Q000502:physiology*; D012212:Rheology / Q000379:methods