What happens to intraocular pressure at high altitude?
Somner JE; Morris DS; Scott KM; MacCormick IJ; Aspinall P; Dhillon B Tennent Institute of Ophthalmology, Gartnavel General Hospital, 1053 Great Western Road, Glasgow, Scotland, UK. john@somner.org.uk PURPOSE: To investigate changes of intraocular pressure on ascent to high altitude. METHODS: The Apex 2 medical research expedition provided the opportunity to measure intraocular pressure (IOP) and central corneal thickness (CCT) in 76 healthy lowlanders. They all arrived in La Paz, Bolivia (altitude, 3700 m), where they spent 4 days before being driven more than 2 hours to the Cosmic Physics Laboratory at Chacaltaya (5200 m) where they stayed for 7 days. IOP and CCT were measured with a hand-held tonometer and ultrasound pachymetry on the first, third, and seventh days at 5200 m. Pre- and postexpedition CCT and postexpedition IOP readings at sea-level were also measured. RESULTS: IOP increased significantly from baseline after acute exposure to altitude before returning to baseline with
