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 volunte ers 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 ey e, measurements were taken at the neuroretinal rim away from visible vessel s. Linear regression analysis, paired two-tailed t test, and two-way analys is of variance were used for statistical analysis. P values less than .05 w ere accepted as statistically significant. RESULTS: There was a significant correlation in square blur rate between th e right and left eyes (r = 0.587, P < .001). Square blur rate in the superi or temporal neuro retinal rim significantly correlated with that in the inf erior 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 superi or neuroretinal rim was higher than that in the inferior neuroretinal rim i n 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 betwee n the right and left eyes and between the superior and inferior temporal ne uroretinal rims. These normal data can be used for understanding physiologi cal ocular hemodynamics. (C) 2000 by Elsevier Science Inc. All rights reser ved.