Short-Term Changes in Intraocular Pressure after Phacoemulsification in Glaucoma Patients.

PURPOSE: To evaluate short-term intraocular pressure (IOP) changes after phacoemulsification in glaucoma and normal patients and the effect of oral acetazolamide (Diamox) to control IOP in these patients. METHODS: 120 patients undergoing cataract surgery were included in this prospective multicenter study involving 6 University Eye Clinics: 60 patients with well-controlled primary open-angle glaucoma (POAG) and 60 controls. Half of the study participants received oral acetazolamide, 250 mg, 1 and 6 h after surgery. The treated and untreated groups were matched for age and density of cataract. All patients underwent a standard phacoemulsification procedure and were checked for IOP with Goldmann tonometry in the morning before surgery and then at 3, 6, 21 and 24 h postoperatively by a masked evaluator. RESULTS: The group with POAG showed a significant postsurgical increase in IOP (p < 0.001) at all time points. Six of thirty (20%) untreated POAG patients showed at least 1 IOP reading above 30 mm Hg whereas acetazolamide significantly reduced postoperative IOP at all time points (p < 0.01) and in no case was IOP >30 mm Hg. The control group had high IOP during the first 6 h (p < 0.01), but normal values thereafter. CONCLUSION: A significant short-term IOP increase may be found after phacoemulsification both in POAG and normal patients; this is not dangerous in normal subjects, but can be potentially dangerous in POAG patients. The use of systemic acetazolamide provided significant control of IOP and could be considered a 'possible standard' management of cataract surgery in POAG patients.