OBJECTIVE To compare anatomical and functional state of eyeballs after congenital cataract extraction and heparin-surface-modified PMMA (HSM-PMMA) or PMMA implanted lenses and to conclude, which type of implants is more advantageous in young patients. METHODS 42 eyes of 30 children at the age of 3-16 years with congenital or developmental cataract after extraction and IOL implantation: I group--HSM-PMMA lenses in 24 eyes, and PMMA lenses in 18 eyes--II group. Mean age in the I group was 6 years and in the II group 8 years, p = 0.07. The presence of cellular and pigment deposits on the IOL surface as a sign of postoperative inflammation was examined by slit-lamp within 1 month after surgery. We have compared the results of visual acuity (V/A), corneal endothelium cell density and posterior capsule state. The examination were done in the short-term follow-up mean 14.1 months (4-24 months) in the I group and mean 32.1 months (16-48 months) in the II group. In the long-term follow-up mean 38 months (30-44 months) in the I group, and mean 56.1 months (40-72 months) in the II group. RESULTS Within first month after operation cellular and pigment deposits on the IOL surface were seen more often in the II group, p = 0.03. Best corrected V/A was comparable in both groups in the short-term and the long-term follow-up. At last visit, mean value of V/A was 0.54 (I group) and 0.42 (II group), p = 0.37. There was no significant difference between central corneal endothelial cell density in both groups: before (2893 +/- 261/mm2 and 2821 +/- 217/mm2, p = 0.143) and after operation (2371 +/- 202/mm2 and 2361 +/- 299/mm2, p = 0.428). In the short-term follow-up, but not longer than within first 12 months after surgery the frequency of clinically significant posterior capsule opacification (PCO) was less in the HSM-PMMA group (8%), than in the PMMA group (33%), p = 0.006. In the long-term follow-up there was no statistically significant difference in PCO appearance between these groups (44% and 50%, p = 0.27). CONCLUSIONS Heparin-surface-modified intraocular lenses reduced postoperative inflammation and delayed the incidence of PCO in children. Heparin-surface-modified intraocular lenses are more advantageous, than PMMA lenses in young patients.