Effect of posture on intraocular pressure in normal and glaucoma patients

Objective To study the effect of posture on intraocular pressure (IOP) in normal and glaucoma patients. Methods Twelve glaucoma patients (24 eyes) at the mean age of 27.5±7.0 years admitted to our hospital from November 2012 to January 2013 served as a glaucoma and 22 normal volunteers (44 eyes) at the mean age of 25.7±4.3 years served as control group in this study. Their IOP at sitting position and horizontal position was measured with a rebound ophthalmotonometer. Their IOP at horizontal position was measured at 5, 10, 15, 20, 25 and 30 min, respectively. Results The average IOP was 16.875±9.441 mmHg (1 mmHg=0.133 kPa) and 17.409±2.576 mmHg, respectively in glaucoma group and control group at horizontal position. The average IOP was 24.500± 9.200 mmHg, 24.083±9.453 mmHg, 25.333±8.004 mmHg, 25.417±7.902 mmHg, 25.167±9.796 mmHg, 22.417±9.681 mmHg respectively and 24.136±3.550 mmHg, 23.273±2.815 mmHg, 22.682±3.772 mmHg, 21.727±3.718 mmHg, 18.955±3.415 mmHg, 18.091±3.407 mmHg respectively in glaucoma group and control group at 5, 10, 15, 20, 25 and 30 min. The IOP reached its peak in glaucoma group at horizontal position at 20 minutes and was signifcantly higher than in control group (P＜ 0.05), and then gradually decreased. Conclusion The IOP is higher in normal and glaucoma patients at horizontal position than at sitting position. The IOP increases at frst and then decreases in the two groups at horizontal position.