OBJECTIVE To evaluate the prognostic factors, effect of timing and outcomes of vitreoretinal surgery for removal of retained lens fragments after phacoemulsification. METHODS A retrospective review of 43 eyes of 43 patients who had vitreoretinal surgery for retained lens fragments after phacoemulsification, between January 1998 and November 2000. RESULTS Seven of the 43 patients underwent vitrectomy on the same day as cataract surgery, 20 in the first week, and 23 after the first week, with a mean of 14.8 days (0-90). Initial visual acuity was < or = 20/400 in 27 (75%, n=36) and intraocular pressure (IOP) > or = 25 mmHg in 22 (61%, n=36) eyes with or without medication. The mean preoperative IOP was 27.4 mmHg. Initial ocular findings included moderate or severe corneal edema in 17 patients (40%), uveitis in 14 (33%), retinal detachment in 1 (2%) and vitreous hemorrhage in 2 (5%). After a mean follow-up of 8.4 months, final best-corrected visual acuity (BCVA) was > or = 20/40 in 24 patients (56%) and < or = 20/400 in 7 (16%). Persistent corneal edema (one eye), cystoid macular edema (four eyes), age-related macular degeneration (one eye) and suprachoroidal hemorrhage (one eye) were the causes of BCVA < or = 20/400. Final mean IOP was 15.2 mmHg and only one case had IOP > 25 mmHg. Uveitis disappeared in all cases (p<0.001), and corneal edema persisted in only one eye. Both the BCVA and IOP differences were significant (p<0.001), but no correlation was found between pre- and postoperative BCVA and IOP as regards vitreoretinal surgery timing, posterior or anterior removal sites and IOL implantation sites or procedures. CONCLUSIONS Vitreoretinal surgery is effective for removing retained lens fragments after phacoemulsification, lowering the IOP and reducing the uveitic reaction and corneal edema. BCVA > or = 20/40 can be reached in at least half the patients.