AIM:To dynamically monitor staffs' intraocular pressure(IOP)on Beijing-Tibet trains at different altitude, and explore the effect and cause of altitude change on the population's IOP.

METHODS: The whole staffs in a set who travelled between Beijing and Lasa were selected randomly, with the height of T1(200m), T2(2500m)and T3(4500m)on approaching and R1(4500m), R2(2500m)on back tracking as monitoring sites for IOP test. Blood pressure, plasma oxygen saturation and heart rate were recorded. Variance analysis and Pearson correlation were applied for statistical analysis, with P<0.05 indicating statistically significant difference.

RESULTS: There was dramatically significant difference between IOP tested at the altitude above 2500m and the lower altitude(200m)(P<0.05), and significant difference between IOP tested at the altitude of 4500m and other monitoring sites(P<0.05). There was no dramatic correlation between IOP and plasma oxygen saturation, heart rate, systolic pressure and diastolic pressure(P>0.05).

CONCLUSION:IOP of train staffs on highland fluctuates as rise of altitude, and it could be increased by high latitude, as may be correlated with low air pressure, change of the biological parameter of eyeball and systemic reaction to high altitude anoxia.