Regulation of subfoveal choroidal blood flow in age-related macular degeneration.
OBJECTIVE
To assess the capability of the subfoveal choroidal circulation to regulate its blood flow in response to an acute increase in ocular perfusion pressure in the eyes of healthy elderly persons or of subjects with neovascular age-related macular degeneration (AMD).


METHODS
Changes of subfoveal choroidal blood velocity (ChBVel), volume (ChBVol), and flow (ChBF) induced by isometric exercise were determined using laser Doppler flowmetry (LDF) in 19 young healthy volunteers (group 1), 24 elderly healthy volunteers with mild macular pigment distribution changes (group 2), and 23 subjects with subfoveal classic neovascularization caused by AMD (group 3).


RESULTS
Isometric exercise induced significant increases in mean ocular perfusion pressure (PPm) of 19.5% +/- 4.9%, 20.2% +/- 3.8%, and 23.2% +/- 4.2%, for groups 1, 2, and 3, respectively (mean +/- 95% confidence interval). In groups 1 and 2, the increase in PPm did not induce significant changes in the mean values of the different LDF parameters. In group 3, however, ChBF increased significantly by 12.4% +/- 5.0%. No significant correlations were found between age and the changes of each of the LDF parameters and of PPm at the end of squatting for the young and elderly healthy groups.


CONCLUSIONS
In response to an acute, moderate increase in PPm induced by isometric exercise, subfoveal choroidal blood flow behaves similarly in young and elderly healthy persons and is not significantly different from its value at rest. In contrast, in patients with neovascular AMD, this flow increases, indicating altered regulation in response to the increase in PPm.
Pournaras
Constantin J
CJ
Department of Ophthalmology, University of Geneva, Geneva, Switzerland. constantin.pournaras@hcuge.ch
Logean
Eric
E
Riva
Charles E
CE
Petrig
Benno L
BL
Chamot
Stéphane R
SR
Coscas
Gabriel
G
Soubrane
Gisèle
G
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D002829:Choroid / Q000098:blood supply*; D020256:Choroidal Neovascularization / Q000503:physiopathology*; D015444:Exercise / Q000502:physiology; D005584:Fovea Centralis / Q000098:blood supply; D006801:Humans; D017078:Laser-Doppler Flowmetry; D008268:Macular Degeneration / Q000503:physiopathology*; D008875:Middle Aged; D012039:Regional Blood Flow / Q000502:physiology