The effect of aging on ocular hemodynamics and on optic nerve head blood flow

A. G. Böhm, L. E. Pillunat, A. U. Köller, A. S. Bernd

Purpose: It is well accepted that aging affects the blood supply in various tissues. The purpose of the study was to examine, whether there are functional alterations of hemodynamics in the optic nerve head.

Methods: One randomly chosen eye of 87 healthy subjects (mean age 37,5y; range 22-70y) without any history of glaucoma or vascular disease was examined. The laser-Doppler-flowmeter according to Riva was used for the measurements. The measured parameter were relative capillary blood flow, relative velocity and relative volume of the moving red blood cells. The measurements were performed at the nasal and temporal neuroretinal rim of the optic nerve head, away from visible vessels. For statistical analysis a Pearson correlation was calculated.

Results: The parameter velocity was (#1: temporal; #2: nasal) #1: 0,315 ±0,1 AU and #2: 0,286 ±0,1AU. The Pearson correlation coefficient between age and velocity was #1: 0,49 and #2: 0,54. The correlation was statistically significant #1: p=0.000001 and #2: p=0.0000006. The parameter volume was #1: 0,396 ±0,193 AU and #2: 0,533±0,381AU. The Pearson correlation coefficient between age and volume was #1: -0,29 and #2: -0,34. The correlation was statistically significant #1: p=0.006 and #2: p=0.001. The parameter flow was #1: 9,636 ±3,001 AU and #2: 10,880±4,975AU. The Pearson correlation coefficient between age and flow was #1: -0,04 and #2: -0,26. The correlation was statistically not significant for #1: p>0.05 but was statistically significant for #2: p=0.01.

Conclusions: With increasing age the velocity of red blood cells increases and the volume decreases in the capillaries of the optic nerve head. Blood flow decreases nasally more than temporally. These results might be explained by a decreasing vessel diameter, which will lead to a reduced reserve capacity and an impaired autoregulation.

Department of Ophthalmology, University of Hamburg, Martinistr. 52, D-20246 Hamburg, Germany

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