Daytime fluctuation of intraocular pressure in patients with primary angle-closure glaucoma after trabeculectomy

To evaluate the daytime fluctuation of intraocular pressure (IOP) in patients with primary angle-closure glaucoma (PACG) after trabeculectomy.

A total of 176 patients with PACG participated in a clinical trial of trabeculectomy with or without releasable sutures. Applanation IOP was measured at 5, 7, and 10 AM, and 2, 6, and 10 PM at 3 months posttrabeculectomy. We documented the mean, peak, and trough IOPs, determined the fluctuation of daytime IOP, and explored the associations of IOP fluctuation with baseline factors.

IOP measurements were obtained in 173 patients. The mean daytime IOP was 13.2±3.7 mm Hg; mean peak IOP 15.1±4.1 mm Hg, mean trough IOP 11.3±3.5 mm Hg, and mean fluctuation 3.8±2.1 mm Hg. Fluctuation was positively correlated with peak (r=0.528, R2=0.28, P<0.001) and mean IOP (r=0.278, R2=0.08, P<0.001), but not with the trough IOP (r=0.015, P=0.843). Fluctuation was lower with extent of bleb (0.6 mm Hg/unit increase in extent; 95% CI, 0.1-1.2 mm Hg) and in blebs with microcysts (1.1 mm Hg less fluctuation; 95% CI, 0.2-1.9 mm Hg). Fluctuation was not associated with sex, age, baseline IOP, extent of peripheral anterior synechia or number of glaucoma medications before surgery, mean deviation of the visual field, vertical cup:disc ratio, or the use of releasable sutures.

The mean fluctuation of daytime IOP after trabeculectomy for PACG was about 4 mm Hg. The fluctuation was positively associated with higher peak and mean IOP and negatively associated with extent of bleb and presence of microcysts.