Influence of mental and physical stress on intraocular pressure - a pilot study

Background The aim of the present study was to examine the influence of phasic stressors on intraocular pressure (IOP). Subjects and methods We exposed 15 ophthalmologically and systemically healthy non-smoking subjects (m:f=8:7; mean age 25.4 years) to both bicycle ergometry physical stress and a computer-game psychological stress. IOP, blood pressure, and subjective stress were measured. To adjust for between-subject variance, we calculated intra-subject z-scores based on IOP values. Because of the habituation occurring during repeated tonometric measurements, we tested the significance of the difference between the observed and expected IOP z-values for each of the stressors. The expected IOP value was the mean of the pre- and post-stress relaxation-period values. Student's t-tests were used to assess the impact of the stressors on blood pressure. Results Both stressors increased the systolic blood pressure, but only under mental stress was the intraocular-pressure increase statistically significant (p = 0.048). Discussion The selective increase in intraocular pressure during mental stress by similar reaction of blood pressure to both stressors is a hint for possible different regulation circuits in the autonomic nerve system for intraocular- and blood pressure, respectively. Additionally, it was possible to demonstrate that mental stress could lead to a rise in intraocular pressure.