Abstract
Abstract: :
Background:Intraocular pressure (IOP) is elevated when the body position is changed from sitting to lying. It is suggested that increased IOP in the lying position may cause the progression of the visual field loss in some cases of glaucoma. Purpose: To investigate the intraindividual difference in the efficacy of four antiglaucomatous agents both in the sitting and lying positions. Design: Randomized, prospective crossover study. Methods: 26 patients: 6 cases of primary open angle glaucoma (POAG), 18 cases of normal tension glaucoma (NTG) and two cases of ocular hypertension (OH), were enrolled and administrated consecutive topical antiglaucomatous agents: latanoprost (LAT), timolol (TIM), nipradilol (NIP) and bunazosin (BUN). The IOP measurement was made in the sitting position and the supine position immediately after the patients were lying down using a pneumatic tonometer. Results: The mean baseline IOP was 17.7 +/– 2.9mmHg (mean +/– SD) in the sitting and 22.3 +/– 2.8 mmHg in the lying position. In the sitting position, LAT significantly reduced IOP by 4.4 +/– 2.3 mmHg compared with TIM (2.7 +/– 2.3mmHg, p=0.005), NIP (2.2+/– 2.3mnHg, p=0.002) and BUN (1.7 +/– 2.5mmHg, p=0.00002). There was no significant difference among, TIM, NIP and BUN (p>0.05). In the lying position, LAT reduced IOP by 3.6 +/– 2.6 mmHg, which was still significantly more effective than NIP (2.5+/– 2.2mnHg, p=0.03) and BUN (2.0 +/– 2.8mmHg, p=0.009). There was no statistically significance between LAT and TIM (3.1 +/– 2.1mmHg, p=0.28). The efficacy of LAT reduced significantly in the lying position (p=0.02) compared with that in the sitting position, however, the efficacy of TIM, LAT and BUN remained unchanged statistically. LAT was chosen as the most effective agent in 19 out of 26 patients in the sitting position, while 15 patients in the lying position. Conclusions: Although LAT was the most effective medicine in both the sitting and the lying position, it reduced the effect significantly in the lying position. The influence of posture was not statistically significant in TIM, NIP and BUN. The most effective medicine in the lying position differed from that in the sitting position in some cases. The IOP may rise considerably in lying position and the efficacy of the medicines varies individually in the body positions.
Keywords: intraocular pressure • drug toxicity/drug effects