Purpose: To evaluate intraocular pressure (IOP) after phacoemulsification and intraocular I lens (IOL) implantation in nonglaucomatous eyes with and without exfoliation. Setting: Department of Ophthalmology, Helsinki University Central Hospital, Helsinki, Finland. Methods: One hundred ninety-six eyes that had phacoemulsification with IOL implantation were examined. Eyes with a history of intraocular disease or surgery that could affect IOP were excluded. The study comprised the remaining 160 eyes: 23 with exfoliation (EXF group) and 137 without exfoliation (non-EXF group). Follow-up data were available for 136 eyes. The same surgeon performed all surgeries. Patients were examined on the first postoperative day and after 1 week, 4 months, and 1.0 to 2.7 years. Results: One day postoperatively, IOP rose in the EXF group from a mean preoperative level of 16.3 mm Hg +/- 2.7 (SD) to 21.0 +/- 8.5 mm Hg, a 28.4% increase (P = .0061). In the non-EXF group, mean IOP rose from 16.2 +/- 3.4 mm Hg to 20.5 +/- 5.7 mm HS, a 29.9% increase (P = .001). In 4 eyes (17.4%) in the EXF group and 8 eyes (5.8%) in the non-EXF group, IOP increased to 30mm Hg or higher at 1 day. After this, significant IOP decreases occurred in both the EXF andnon-EXF group, respectively as follows: 14.2 +/- 3.0 mm Hg (12.0% decrease from preoperative value; P = .001) and 15.0 +/- .9 mm Hg (5.9%; P = .001) 1 week postoperatively; 12.8 +/- 2.7 mm Hg (20.2%; P = .0002) and 13.8 +/- 2.7 mm Hg (13.2%; P = .001) after 4 months; and 12.3 +/- 2.6 mm Hg (23.2%; P = .0001) and 12.7 +/- 2.7 mm Hg (21.2%; P = .001) after 1.0 to 2.7 years. There was no significant difference between the 2 groups. Conclusion: Alter phacoemulsification with IOL implantation, IOP decreased significantly and remained lower than preoperatively in eyes with and without exfoliation, One day postoperatively, transient pressure peaks were more common in eyes with exfoliation. One eye without exfoliation developed glaucoma. (C) 2001 ASCRS and ESCRS.