The effect of lateral decubitus position on intraocular pressure in healthy young subjects

Abstract

To investigate the effect of change of body posture from supine to lateral decubitus position (LDP) on intraocular pressure (IOP) in healthy young subjects. We evaluated 38 eyes of 19 healthy young Korean subjects. IOP was measured using Tonopen XL in both eyes in the sitting and supine position, 5 and 30 min after right LDP and 5 min after returning to the supine position. A week later, IOP was measured in the same sequence except that the subjects assumed the left LDP. The eye on the lower side in the LDP was termed as a dependent eye. The mean IOP of the dependent eyes increased significantly at 5 min after changing from supine to right (16.26 ± 2.73 mmHg versus 18.54 ± 2.95 mmHg, p < 0.01) or left LDP (15.53 ± 2.41 mmHg versus 17.53 ± 3.37 mmHg, p < 0.01); this IOP increase in the dependent eyes persisted at 30 min after changing to right (18.47 ± 2.97 mmHg, p < 0.01) or left LDP (17.79 ± 2.20 mmHg, p < 0.01). Upon returning to the supine position, IOP of the dependent eyes decreased significantly (16.83 ± 2.67 mmHg, p < 0.01 for right LDP and 16.47 ± 2.32 mmHg, p < 0.01 for left). However, this effect of the positional change was not found in the non-dependent eyes (all, p > 0.05). Mean IOP in the dependent eye was significantly higher than that in the non-dependent eye at 30 min after changing to the right (+0.89 ± 1.52 mmHg) or left LDP (+1.84 ± 2.03 mmHg). The postural change from supine to LDP significantly increased IOP of the dependent eyes.