The Effect of Age on Optic Nerve Head Blood Flow

To examine whether optic nerve head blood flow changes with aging. One randomly chosen eye of each of 103 healthy subjects (age range, 22-76 years) was examined by laser Doppler flowmetry. Relative capillary blood flow, velocity, and volume of the moving red blood cells were measured at the temporal and nasal neuroretinal rim of the optic nerve head. For statistical analysis, linear regression analysis and partial correlations were calculated. Velocity increased with age. The Pearson correlation coefficient (R) between age and velocity was 0.49 temporally and 0.56 nasally. The correlation was significantly different from 0 (both P < 0.0005). Volume decreased with increasing age. The Pearson correlation coefficient between age and volume was -0.47 temporally and -0.40 nasally. The correlation was significantly different from 0 (both P < 0.0005). Flow decreased with increasing age. The Pearson correlation coefficient between age and flow was -0.27 temporally and -0.31 nasally. The correlations were significantly different from 0 (P = 0.006 and P = 0.002, respectively). Partial correlation coefficients between the perfusion parameters and age, after correcting for systolic and diastolic blood pressure, heart rate, gender, and IOP, were similar compared to the Pearson correlation coefficients and remained statistically significant. The perfusion of the optic nerve head is altered with increasing age. The results suggest that the blood supply is reduced in elderly subjects.