Contrast sensitivity with silicone and poly(methyl methacrylate) intraocular lenses

PURPOSE: To compare the optical performance of silicone intraocular lenses (IOLs) with that of conventional poly(methyl methacrylate) (PMMA) IOLs. SETTING: University hospital outpatient cataract clinic. METHODS: Ninety-one patients were randomly assigned to receive a PMMA IOL (n = 48 eyes) or a silicone IOL (n = 43 eyes). Contrast sensitivity was evaluated 4 months after surgery using the Vistech sinusoidal-grating chart and the Pelli-Robson letter sensitivity chart. RESULTS: No between-group differences were found using the Vistech test. Using the Pelli-Robson test, mean uncorrected contrast sensitivity was 1.59 log units +/- 0.13 (SD) in the PMMA group and 1.53 +/- 0.15 log units in the silicone group. Mean best corrected contrast sensitivity was 1.67 +/- 0.11 and 1.63 +/- 0.16, respectively. The differences between groups using the Pelli-Robson test were statistically significant (P < .05). No correlation was found between reduced contrast sensitivity and brownish discoloration or thickness of silicone IOLs or posterior capsule fibrosis. CONCLUSION: Contrast sensitivity was lower in patients with silicone IOLs than in those with conventional PMMA lenses.