Longitudinal observation of intraocular pressure variations with acute altitude changes

Table 2 Comparison of baseline parameters among three groups measured at their native hospitals (mean ± SD)

Parameters	LA group	HA group	VHA group	P value	Post hoc analysis
n	17 (34 eyes)	22 (44 eyes)	19 (38 eyes)
SpO2 (%)1	97.06 ± 0.43	94.55 ± 1.18	90.05 ± 2.09	< 0.001	A > B > C
IOP (mmHg)2	18.4 ± 2.4	12.2 ± 2.4	11.5 ± 1.8	< 0.001	A > B, C
OPP (mmHg)2	36.5 ± 6.3	47.9 ± 7.3	49.2 ± 9.2	< 0.001	A > B, C
SBP (mmHg)3	109.7 ± 11.5	118.6 ± 14.9	118.3 ± 18.3	0.149	NS
DBP (mmHg)3	68.7 ± 10.3	76.1 ± 10.3	77.5 ± 14.5	0.069	NS
MBP (mmHg)3	82.4 ± 10.2	90.2 ± 11.2	91.1 ± 14.9	0.051	NS
Pulse rate (bpm)3	78.6 ± 9.1	79.6 ± 10.6	87.6 ± 8.5	0.009	A, B < C
Erythrocyte (1012/L)1	4.58 ± 0.6	5.24 ± 0.63	5.67 ± 0.62	< 0.001	A < B, C
Hemoglobin (g/L)1	137.63 ± 21.14	157.09 ± 20.26	180.84 ± 23.37	< 0.001	A < B < C

¹Kruskal–Wallis test with post hoc Dunn multiple comparisons.

²Mixed linear model analysis.

³One-way ANOVA with post hoc least significant difference analysis. SpO₂: Pulse oxygen saturation; IOP: Intraocular pressure; OPP: Ocular perfusion pressure; SBP: Systolic blood pressure; DBP: Diastolic blood pressure; LA: Low-altitude; HA: High altitude; VHA: Very high altitude; A: Low-altitude group; B: High altitude group; C: Very high altitude group; NS: Not significant.