Age-related normal tolerance intervals for retinal vascular response to systemic autonomic nerve stimulation

This study establishes the age-adjusted tolerance intervals for retinal vascular responses to sustained handgrip contraction (a test of sympathetic nerve function). Forty adult subjects (mean age: 39.7 +/- 14.1 years, range: 20 to 72 years; 19 males) were included in the final analysis. Mean percentage calibre change in response to sustained handgrip contraction in this population was -5.61% with a significant correlation between subject age and percentage retinal vessel calibre change (p less than 0.001). Mean retinal arteriolar calibre change in response to systemic autonomic stimulation varied significantly with age: between -8.48% at age 20 years and -2.06% at age 70 years with a mean of -5.95% at the mean age of 39.7 years. The standard deviation is 3.04% and the 95% confidence intervals were set between +/-6.17%. This autoregulatory reflex appears to be inversely related to age.