The Effect of Lateral Decubitus Position on Intraocular Pressure in Patients with Untreated Open-Angle Glaucoma

PURPOSE: To investigate the effect of change of body posture from the supine to the lateral decubitus position on intraocular pressure (TOP) in patients with open-angle glaucoma. DESIGN: Prospective, observational case series. METHODS: Setting. Institutional. Participants. Forty-four eyes of 22 patients with newly diagnosed bilateral open-angle glaucoma. Observation procedures. IOP was measured using the Tono-Pen XL (Reichert Inc) in both eyes 10 minutes after assuming each position: sitting, supine, right lateral decubitus, supine, left lateral decubitus, and supine. By comparing the mean deviation (MD) of Humphrey visual field between both eyes of a patient, eyes were classified into either worse-MD eye or better-MD eye. Main outcome measures. Magnitude of IOP alterations by postural changes and intereye difference of IOP with each posture. RESULTS: The mean SD IOP of the dependent eyes (eye on the lower side in the lateral decubitus position) increased after changing from the supine to the right lateral decubitus position (19.1 +/- 2.6 mm Hg vs 21.0 +/- 2.7 mm Hg; P = .019) or the left lateral decubitus position (18.6 +/- 2.9 mm Hg vs 20.6 +/- 3.1 mm Hg; P = .002). The mean IOP of the dependent eyes was significantly higher than that of the nondependent eyes in the lateral decubitus positions (right lateral decubitus, + 1.2 mm Hg; left lateral decubitus, +1.6 mm Hg; both, P < .05). Compared with the better-MD eyes, the worse-MD eyes showed a tendency for greater TOP rise with positional change from the supine to lateral decubitus position (2.3 +/- 2.2 mm Hg vs 1.5 +/- 2.1 mm Hg; P = .065). CONCLUSIONS: The postural change from the supine to lateral decubitus position may increase the IOP of the dependent eyes in patients with open-angle glaucoma. (Am J Ophthalmol 2013;155:329-335. (c) 2013 by Elsevier Inc. All rights reserved.)