Relation between office intraocular pressure and 24-hour intraocular pressure in patients with primary open-angle glaucoma treated with a combination of topical antiglaucoma eye drops

PURPOSE: To determine the relation between office intraocular pressure (IOP) and 24-hour IOP in patients with primary open-angle glaucoma (POAG) treated with 3 kinds of antiglaucoma eye drops. PATIENTS AND METHODS: Subjects were 42 patients with POAG (71 eyes). All were being treated with 3 different topical antiglaucoma eye drops (latanoprost, beta-blocker, and carbonic anhydrase inhibitor). Twenty-four-hour IOP values were obtained in the sitting position with a Goldmann applanation tonometer at 3-hour intervals. RESULTS: Maximum 24-hour IOP (mean+/-SD) was 19.76+/-5.65 mm Hg, minimum 24-hour IOP was 13.06+/-4.75 mm Hg, mean 24-hour IOP was 16.30+/-4.90 mm Hg, and 24-hour IOP fluctuation was 6.70+/-2.81 mm Hg. Office IOP was 16.23+/-4.58 mm Hg, and office IOP fluctuation was 2.75+/-1.68 mm Hg. There was no significant difference between office IOP and mean 24-hour IOP (P=0.93). There was no correlation between office IOP and 24-hour IOP fluctuation (r=0.15; P=0.25) or between office IOP fluctuation and 24-hour IOP fluctuation (r=0.19; P=0.17). Maximum 24-hour IOP occurred during office hours in 22 eyes (33.8%). The frequency of maximum 24-hour IOP occurring during office hours was significantly less than that of minimum 24-hour IOP (P<0.001). CONCLUSIONS: In POAG patients treated with 3 kinds of antiglaucoma eye drops, office IOP was similar to mean 24-hour IOP. However, it was difficult to estimate 24-hour IOP fluctuation and maximum 24-hour IOP on the basis of office IOP.