Age-related differences in central corneal thickness alterations caused by short-term hypobaric hypoxia

To assess the effect of short-term hypobaric hypoxic exposure on central corneal thickness (CCT) in healthy participants in 2 different age groups.

Seventy eyes in 35 healthy men were investigated. Twenty participants (mean age 22.8 +/- 0.6 years) comprised 1 group, and 15 (mean age 32.1 +/- 2.8 years) comprised another group. CCT was measured via ultrasound pachymetry initially at local ground level (792 m above sea level), then during short-term hypobaric hypoxic exposure (equivalent to 9144 m altitude), and then again under ground level conditions. The mean of 10 consecutive CCT measurements in each eye under each set of conditions was used in statistical analysis.

In the younger group, initial CCT was 561.5 +/- 36.1 microm. This increased to 562.3 +/- 36.7 microm under hypobaric hypoxic conditions, and after the return to local ground level conditions, CCT decreased to 560.1 +/- 34.5 microm. CCT values under hypobaric hypoxic conditions were not significantly different from those measured before or afterward (P > 0.05). In the older group, initial CCT was 566.0 +/- 33.7 microm. This increased to 576.9 +/- 28.5 microm under hypobaric hypoxic conditions, and after the return to local ground level conditions, CCT decreased to 567.9 +/- 33.3 microm. In the older group, CCT values under hypobaric hypoxic conditions were significantly greater than those measured initially (P < 0.001) or afterward (P < 0.01). In both age groups, initial CCT did not differ significantly from final CCT (P > 0.05).

Short-term hypobaric hypoxic exposure increased CCT significantly in the older age group, whereas it yielded a nonsignificant minor increase in the younger age group.