Longitudinal observation of intraocular pressure variations with acute altitude changes

Figure 2 Longitudinal observation of intraocular pressure changes in the low altitude and high altitude groups. The figure elucidated a gradual and significant decrease in intraocular pressure (IOP) from 44 m [low altitude (LA) baseline] through 2261 m to 3750 m above sea level (ASL) and remained at the 3750 m ASL for 2 d. When the LA group flew back to 2261 m ASL, the IOP did not change. When the LA group flew back to 44 m, the IOP increased but was still lower than LA baseline. The IOPs in the LA group at 2261 m and 3750 m ASL were comparable to that in the native residents. No significant changes were found in the IOP of the high altitude group throughout the observation time at 3750 m compared to that at 2261 m ASL. IOP: Intraocular pressure; LA: Low altitude; HA: High altitude; VHA: Very high altitude.