Purpose: The purpose of this study was to evaluate 24-hour intraocular pressure (IOP) control in patients with moderate to severe open-angle glaucoma treated by trabeculectomy and mitomycin C versus maximum tolerated medical therapy.
Design: Prospective observational study.
Participants: Thirty surgical patients and 30 medically treated patients with advanced glaucoma.
Methods: Patients successfully treated with initial trabeculectomy or patients considered successfully treated on maximum tolerated medical therapy (2-4 medicines) were enrolled. We performed IOP measurements at 6 am, 10 am, 2 pm, 6 pm, 10 pm, and 2 am. Patients were matched by IOP +/- 1 mmHg at 10 am.
Main outcome measures: A 24-hour IOP control.
Results: The surgical patients had a mean diurnal IOP of 12.1+/-2.2 versus 13.5+/-2.0 mmHg for the matched medically treated patients (P = 0.0001). The average maximum IOP for the surgical group was 13.4+/-2.3 and 16.3+/-3.2 mm Hg for the medical group (P<0.0001). The 24-hour range of IOP for the surgical group was 2.3+/-0.8 and 4.8+/-2.3 mmHg for the medical group (P<0.0001). Except at 10 am (P = 0.5), the surgical group had a statistically lower IOP at each measured time point. Eleven (37%) patients in the medically treated group, and none in the surgically treated group, had peak IOPs > or = 18 mmHg. The majority of peak IOPs (10 of 11) occurred outside of normal office hours.
Conclusions: This study suggests that a well-functioning trabeculectomy provides a statistically lower mean, peak, and range of IOP for the 24-hour day than maximum tolerated medical therapy in advanced glaucoma patients.