Contrast sensitivity in 64 patients aged from 50 to 69 years with an intraocular lens (IOL) was studied. There were 23 eyes with a silicone and 31 eyes with a polymethylmethacrylate (PMMA) IOL. Ten patients had a silicone IOL in one eye and a PMMA IOL in the other. Contrast sensitivity was examined with the Vistech far vision VCTS 6500 test. The contrast sensitivity test results in silicone and PMMA IOL eyes were in all cpd (cycles per degree) lines significantly worse than in normal eyes except in the 60-year-old group in the 18-cpd line. The contrast sensitivity test results were in all cpd lines better in the silicone IOL eyes than in the PMMA IOL eyes, but it reached significance only in the 3-cpd line. In the 10 patients with the silicone lens in one and the PMMA lens in the other eye, the test results were also better in the silicone IOL eye; it also reached significance only in the 3-cpd line.