INFLUENCE OF AGE ON RETINAL AND OPTIC-NERVE HEAD BLOOD-CIRCULATION

Purpose: To quantify the influence of age on the retinal perfusion, th e authors investigated the microcirculation of the retina and optic ne rve head (ONH) and the blood flow velocity in the central retinal arte ry (CRA). Method: The authors examined two groups of healthy volunteer s. In group 1 (n = 36 eyes of 36 subjects; mean age, 41.5 +/- 14.9 yea rs), retinal and ONH microcirculation was analyzed by scanning laser D oppler flowimetry. In group 2 (n = 49 eyes from 49 subjects; mean age, 44.4 +/- 15.4 years), CRA blood flow velocity was examined using puls ed Doppler sonography. Results: Blood flow velocity of the CRA showed a negative correlation to age (systolic velocity, r = -0.47, P = 0.001 ; diastolic velocity, r = -0.49, P = 0.001). The slope of the linear r egression was -0.62 cm/second per 10 years for systolic blood velocity and -0.51 cm/second for diastolic blood velocity. Resistivity index ( RI) (RI = [systolic velocity - diastolic velocity]/systolic velocity) as a marker of the rigidity of the vessel increased significantly with age (r = 0.40, P = 0.004). The slope was 0.03 per 10 years. Retinal m icrocirculation (flow omega(ret)) decreased significantly with age (r = -0.63, P = 0.00001). The slope was -34.9 [AU] per 10 years. Optic ne rve head blood flow showed no significant correlation to age (r = -0.3 0, P = 0.071). Conclusion: The authors' data indicate that there is a significant decrease of retinal and CRA blood flow of approximately 6% to 11% per decade. Optic nerve head blood flow seems not to be influe nced by age.