Exertion Does Not Affect the Optic Nerve Sheath Diameter in Healthy Participants

The purpose of this study was to determine if exertion influences the ONSD in healthy individuals. Healthy adults were eligible for inclusion. Activities were performed by each participant for 60 seconds and were as follows: sprinting, holding a 10-pound weight with both arms outstretched parallel to the floor, a Valsalva maneuver, a plank position, and positioning the head down thirty degrees with the participant in the supine position. Two-dimensional ultrasound images visualizing the optic nerve sheath (ONS) were recorded in three orientations and averaged to determine the mean ONSD 3 millimeters posterior to the retina. Baseline measurements ranged from 3.57 to 4.90 millimeters. Post-exertion measurements ranged from 3.60 to 4.93 millimeters. Based on a one sample paired t-test the difference between baseline and post-activity measurements were not significant. This study demonstrates that ONSD measurements by ultrasound do not change in healthy individuals in response to exertion.