Measurement of microcirculation in optic nerve head by laser speckle flowgraphy in normal volunteers

PURPOSE: To report blood flow in the optic nerve head between the right and left eyes or the superior and inferior neuroretinal rims in normal volunteers using laser speckle flowgraphy. METHODS: This prospective study included 120 eyes of 60 normal volunteers (mean age, 50.0 +/- 16.9 years; range, 21 to 77 years). The square blur rate was measured by laser speckle flowgraphy (Kyushu Institute of Technology, Iizuka, Japan). The sequence of eye measurements was randomized. In each eye, measurements were taken at the neuroretinal rim away from visible vessels. Linear regression analysis, paired two-tailed t test, and two-way analysis of variance were used for statistical analysis. P values less than .05 were accepted as statistically significant. RESULTS: There was a significant correlation in square blur rate between the right and left eyes (r = 0.587, P < .001). Square blur rate in the superior temporal neuro retinal rim significantly correlated with that in the inferior temporal neuroretinal rim in each of the right (r = 0.546, P < .001) and left (r = 0.465, P < .001) eyes. Square blur rate in the right eye was higher than that in the left eye (P = .049). Square blur rate in the superior neuroretinal rim was higher than that in the inferior neuroretinal rim in both the right (P = .035) and left (P = .005) eyes. CONCLUSION: There were statistically significant differences of optic nerve head blood flow in normal volunteers using laser speckle flowgraphy between the right and left eyes and between the superior and inferior temporal neuroretinal rims. These normal data can be used for understanding physiological ocular hemodynamics. (C) 2000 by Elsevier Science Inc. All rights reserved.