Relationship of the 24-Hour Pattern of Intraocular Pressure with Optic Disc Appearance in Primary Open-Angle Glaucoma

Purpose: To study the relationship between the 24-hour pattern of intraocular pressure (IOP) with optic disc appearance in primary open-angle glaucoma (POAG) patients. Design: Observational clinical study. Participants: Seventy-five eyes of 45 POAG patients. Methods: Patients underwent 24-hour IOP assessment in a sleep laboratory. Two observers classified the optic disc appearance for each eye as either concentric or nonconcentric. The IOP measurements were obtained with the subjects in the supine and sitting positions during the diurnal period and in the supine position during the nocturnal period. The mean, peak, and trough IOP and IOP range (peak through trough) were calculated for the office-hour period (9 AM to 4 PM), the diurnal period (7 AM to 11 PM), the nocturnal period (11 PM to 7 AM), and the 24-hour period. Further, the difference in supine and sitting IOP during the diurnal periods was calculated, and generalized estimating equations were used to compare IOP measurements in both groups. Main Outcome Measures: Diurnal and nocturnal IOP measurements. Results: Forty eyes were classified as having concentric optic disc appearance and 35 eyes as having nonconcentric optic disc appearance. The mean nocturnal IOP was significantly greater in the concentric group (mean +/- standard deviation [SD], 24.0 +/- 3.8 mmHg) compared with the nonconcentric group (mean +/- SD, 21.9 +/- 1.9 mmHg; P = 0.004). Most IOP peaks of patients with the concentric optic disc appearance occurred during the nocturnal period, as opposed to the diurnal period of patients with the nonconcentric optic disc appearance. Conclusions: Concentric optic disc appearance may be associated with higher nocturnal IOP compared with nonconcentric optic disc appearance. Financial Disclosure(s): The author(s) have no proprietary or commercial interest in any materials discussed in this article. Ophthalmology 2009;116:833-839 (C) 2009 by the American Academy of Ophthalmology.