Lovastatin has been associated with development of subcapsular cataract in dogs given high doses. To test the cataractogenic potential of lovastatin in humans, 192 patients were divided into 2 groups, A (N = 94) and B (N = 98), 1 taking 40 mg/day of lovastatin and 1 taking placebo. Both groups were enrolled for 2 years in this double-blind, randomized study and were followed with eye examinations including assessment of visual function, Lens Opacities Classification System II (LOCS II) cataract and nuclear color classification, and computerized lens image analysis. There were no statistically significant differences in visual function between the two groups. Similarly, cataract progression, assessed by LOCS II measurement and by computerized measurements of cataract, showed no important differences between the treatment groups. These data show no cataractogenic effect of lovastatin in humans.