Ocular blood flow changes after dynamic exercise in humans.
OBJECTIVE
To investigate control mechanisms for ocular blood flow changes after dynamic exercise using two different methods.


METHODS
Changes over time in the tissue blood flow in the retina and choroid-retina of healthy volunteers were determined after dynamic exercise (Master's double two-step test), using scanning laser Doppler flowmetry (SLDF) and laser speckle flowgraphy (LSFG). Changes in intraocular pressure (IOP), blood pressure, plasma CO(2) gas concentration (pCO(2)), and levels of nitric oxide (NO) metabolites were examined.


RESULTS
Retinal blood flow measured by SLDF increased significantly only at 15 min after exercise. In contrast, normalized blur (NB) values in the choroid-retina, obtained by LSFG, increased significantly up to 60 min after exercise. Ocular perfusion pressure (OPP), calculated from IOP and blood pressure, increased significantly immediately and 15 min after exercise. The plasma NO metabolite levels increased significantly, although pCO(2) levels were unchanged.


CONCLUSIONS
Dynamic exercise changes OPP and produces increased tissue blood flow in the retina in the immediate postexercise period, while blood flow increases more persistently in the choroid-retina. Difference in control of blood flow in these two regions may be related to stronger autoregulatory mechanism of blood flow in the retina. Nitric oxide may play a role in the regulation of blood flow.
Okuno
T
T
Department of Ophthalmology, Osaka Medical College, Takatsuki, Osaka, Japan.
Sugiyama
T
T
Kohyama
M
M
Kojima
S
S
Oku
H
H
Ikeda
T
T
D000328:Adult; D001783:Blood Flow Velocity / Q000502:physiology*; D001784:Blood Gas Analysis; D001794:Blood Pressure / Q000502:physiology; D002245:Carbon Dioxide / Q000097:blood; D002829:Choroid / Q000098:blood supply*; D015444:Exercise / Q000502:physiology*; D005260:Female; D006801:Humans; D007429:Intraocular Pressure / Q000502:physiology; D017078:Laser-Doppler Flowmetry; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000097:blood; D012016:Reference Values; D012039:Regional Blood Flow; D012160:Retina / Q000502:physiology*
D002245:Carbon Dioxide; D009569:Nitric Oxide