Timolol and postoperative intraocular pressure.

We studied the effect of timolol instillation at surgery on the acute postoperative pressure rise following extracapsular cataract extraction (ECCE) and posterior chamber lens implantation. The intraocular pressure (IOP) was measured daily during the first week following surgery in 85 eyes. Timolol was instilled immediately following surgery in 34 eyes; the remaining 51 served as controls. The mean preoperative IOP was 18.7 mm Hg in the treated and control groups. The mean IOP on the first day following surgery was 20.0 mm Hg in the timolol group and 20.7 mm Hg in the control group. Twenty-six percent of the timolol group had a pressure greater than 23.0 mm Hg (mean 35.6 mm Hg); 33% of the control group had a pressure greater than 23.0 mm Hg (mean 31.0 mm Hg). The IOP in all treated and untreated patients with ocular hypertension on the first day following surgery returned to normal within three days. Timolol, therefore, had no effect on acute postoperative pressure elevation following ECCE and posterior chamber lens implantation.