Fig. 1: Optic Nerve sheath complex variation in volunteers during 30, 60, 90 days of the head down tilt bed rest and 2, 7, 14, 30, 90, 180 days of recovery.

Error bars represent the 95% confidence interval of the mean. The “*” and “#” represent ONSD (a), OND (b), ONSSW (c) at 3 mm and 5 mm posterior to the optic disc, respectively, which significantly increased in comparison to the values on day 180 of the recovery time (R + 180). The “&” indicates ONSSA (d) between 3 to 5 mm posterior to the optic disc significantly increased compared with that on R + 180. ONSD optic nerve sheath diameter, OND optic nerve diameter, ONSSW the width of the optic nerve subarachnoid space, ONSSA the transversal area of the optic nerve subarachnoid space.