OBJECTIVE The degree of cell adhesion to intraocular lenses (IOLs) was studied through the cell culture system and the morphology of adhering cells was studied using a light electron microscope and a scanning electron microscope. METHODS Human lens epithelial cells were used as materials. The IOL materials were classified into four groups: polymethylmethacrylate (PMMA), heparin surface modified PMMA, surface passivated PMMA, and silicone. RESULTS PMMA showed greater adhesion than did the other materials. Cells hardly adhered to silicone. Use of a light electron microscope and a scanning electron microscope revealed that cells adhered uniformly to the surface of PMMA and were elongated, but did not adhere uniformly to IOLs of other materials. Only a few cells without the tendency of elongation were noted on the silicone the second day after culture. The 14th day after culture, the surfaces of IOLs, except those of silicone, were covered with cells. CONCLUSIONS Such differences in the surface adhesion and morphology of cells adhering to the IOL surface are important in evaluating IOL biocompatibility.