Abstract
Purpose:
To compare the effect of body position, particularly the prone face-down position, on intraocular pressure in treated low-tension glaucoma patients.
Methods:
This was a prospective study approved by the Vanderbilt Institutional Review Board (clinicaltrials.gov NCT00338065). Measured eyes of all 10 consented subjects were under treatment with topical and/or oral IOP-lowering agents, with or without history of past glaucoma surgery. Subjects were placed in 5 different positions (standing, sitting, supine, prone face down, and supine propped with two pillows) for 10 minutes each. At the end of the ten minutes, IOP was measured with a Tonopen XL, and blood pressure and heart rate were measured with an automated sphygmomanometer. One-Way Repeated Measures Analysis of Variance with Bonferroni was performed using SigmaPlot 12.5 (Systat Software, San Jose, CA).
Results:
Mean IOP in each position was as follows: standing 11.1 ± 2.0 mmHg; sitting 11.3 ± 2.1 mmHg; supine 13.7 ± 2.2 mmHg; supine propped with pillows 13.6 ± 2.2 mmHg; prone 19.0 ± 2.8 mmHg. IOP in the prone position was statistically significantly higher than in all other positions (p < 0.001). IOPs while supine or supine propped with pillows were each significantly higher than in either the standing or sitting positions (p ≤ 0.018 for each intergroup comparison). IOP was not significantly different in the standing position compared to the sitting position (p = 1.0), nor was IOP significantly different in the supine position compared to supine propped with pillows (p = 1.0).
Conclusions:
The prone position drastically increases intraocular pressure, even in treated patients with good IOP control. IOP increase of this magnitude, potentially for several hours every day, indicates that sleep position perhaps should be ascertained in all glaucoma patients and may warrant behavior modification to avoid the prone sleep position, particularly in patients with advanced glaucoma.