Dampening of Diurnal Intraocular Pressure Fluctuation by Combined Trabeculotomy and Sinusotomy in Eyes With Open-angle Glaucoma

Purpose: Large diurnal intraocular pressure (IOP) fluctuation (Delta IOP) is believed to be one of the causes of progression in glaucomatous changes. Some fully medicated glaucoma patients whose IOPs are controlled during the regular office hours (10:00 to 16:00 h) still have progression in glaucomatous changes and IOP elevation during off-office hours. The purpose of this study was to determine whether Delta IOP is dampened after combined trabeculotomy and sinusotomy (LOT+SIN) in glaucoma patients with low IOPs during the regular office hours. Patients and Methods: Fourteen eyes of 8 open-angle glaucoma patients who had large Delta IOP despite low IOPs during the office hours were studied. The IOP was measured every 3 hours for 24 hours before and >3 months after the operation. The IOPs were measured in the sitting position with a Goldmann applanation tonometer. All patients underwent LOT+SIN. Results: All patients had IOP elevations >20mm Hg between 0:00 and 3:00 hours before the operation, and none had an IOP peak after the operation. The postoperative mean IOP (16.5 +/- 1.7 to 13.9 +/- 2.0mm Hg, P=0.00064), the maximum IOP (21.9 +/- 2.4 to 16.1 +/- 2.5mm Hg, P=0.0020), and Delta IOP (8.9 +/- 2.7 to 4.3 +/- 1.2mm Hg, P=0.0032) were significantly lower than the preoperative values. However, the minimum IOP was not reduced significantly (13.0 +/- 1.9 to 11.7 +/- 1.7mm Hg). Conclusions: The diurnal Delta IOPs are dampened by LOT+SIN in glaucoma patients with controlled IOPs during regular office hours. These results indicate that these surgical procedures can be used for the treatment of open-angle glaucoma patients.