Intraocular Pressure Elevation within the First 24 Hours after Cataract Surgery in Patients with Glaucoma or Exfoliation Syndrome

Abstract

To investigate whether eyes with glaucoma or exfoliation syndrome without glaucoma are prone to exhibit intraocular pressure (IOP) elevation shortly after cataract surgery and, if so, whether timolol maleate 0.5% reduces these spikes. Prospective randomized double-masked clinical trial. One hundred twenty-two patients with normal eyes, medically well-controlled glaucoma, or exfoliation syndrome who underwent uneventful phacoemulsification cataract extraction. Patients were randomly assigned to an immediately postoperative drop of either timolol maleate 0.5% or no treatment. Intraocular pressure was measured preoperatively and 4, 8, and 24 hours and 1 week later. Intraocular pressure measurements. The changes in postoperative IOP over time differed significantly between glaucoma, exfoliation syndrome, and normal (P = 0.005). Intraocular pressure was significantly lower in the normal group (n = 25) than in both the glaucoma (n = 18) and exfoliation syndrome (n = 19) groups (P<0.001). With 1 drop of prophylactic timolol maleate 0.5% at completion of surgery, the normal group (n = 25) again had IOP significantly lower than those of the glaucoma (n = 15) and exfoliation syndrome (n = 20) groups (P<0.001). Treatment with timolol maleate 0.5% significantly changed postoperative IOP over time in the glaucomatous eyes (P = 0.003), but it made no difference in the exfoliation syndrome (P = 0.4) or normal (P = 0.5) eyes. Intraocular pressure > 25 mmHg did not occur among normal eyes. Intraocular pressure > 25 mmHg and > 30 mmHg occurred in 10 (55%) and 5 (28%) glaucoma patients, respectively, and 5 (27%) and 2 (11%) exfoliation syndrome patients, respectively. Timolol maleate 0.5% eliminated IOP spikes > 30 mmHg and reduced the frequency of IOP > 25 mmHg in both groups to 14% in the glaucoma group and 5% in the exfoliation syndrome group. Most IOP elevation occurred at 4 hours postoperatively. The mean IOP was <20 mmHg in all groups 1 day postoperatively. Medically well-controlled glaucoma patients and patients with exfoliation syndrome may experience IOP elevation shortly after cataract surgery. Instillation of timolol maleate 0.5% at the end of the procedure in this series eliminated IOP > 30 mmHg, but IOP elevation below that level can still occur.