BACKGROUND: The precise effect of cataract surgery with implantation of an intraocular lens (IOL) on the course of uveitis is not well known. Laser flare photometry allows quantitative assessment of intraocular inflammation. The aim of this study was to determine the effect of cataract surgery with IOL implantation on the disease course and level of inflammation in chronic uveitis, using laser flare photometry monitoring. METHODS: The charts of all patients who underwent surgery for secondary uveitic cataract between 1990 and 1994 (24/558 [4.3%]) were reviewed. Only eyes that had received standardized perioperative steroid treatment and had systematic laser flare photometry follow-up were included. Cataracts due to Fuchs' heterochromic cyclitis were excluded. Visual acuity, flare values and recurrence of flare episodes were compared before and after cataract surgery, and postoperative data were compared between eyes that received heparin-coated IOLs and those that received uncoated IOLs. RESULTS: Nineteen eyes of 16 patients met the inclusion criteria. The mean length of the pre- and- postoperative follow-up periods was 779 and 444 days respectively. The mean visual acuity increased from 0.2 (standard error of the mean [SEM] 0.2) preoperatively to 0.8 (SEM 0.3) postoperatively (p < or = 0.001). The mean flare value decreased from 58.6 (SEM 18.6) photons/ms during preoperative follow-up to 29.7 (SEM 7.8) photons/ms during postoperative follow-up (p < or = 0.006). The mean number of recurrences per 6 months decreased from 0.27 (SEM 0.03) preoperatively to 0.12 (SEM 0.01) postoperatively (p < or = 0.05). The difference in the postoperative recurrence rate between the eyes that received coated IOLs (0.0) and those that received uncoated IOLs (0.18 [SEM 0.02]) approached statistical significance (p < or = 0.054). INTERPRETATION: Quantitative assessment of inflammation by laser flare photometry in patients undergoing surgery for uveitic cataract showed that there was significantly less inflammation and fewer recurrences postoperatively and that recurrences were less severe.