BACKGROUND Glare disability and appearance of halos may be side-effects of cataract, but were also described in patients with multifocal IOLs. The aim of this study was to compare glare sensitivity and halo size in phakic and pseudophakic eyes. METHODS Contrast sensitivity without and with glare and halos around a light source were measured by means of a new computerized test in patients with cataract, monofocal IOLs, multizonal progressive and diffractive multifocal IOLs as well as in a younger control group of subjects with clear lenses. Glare acuity was measured at three different luminance settings. RESULTS Patients with cataract showed the most important reduction in contrast sensitivity, noticed significantly larger halos and were more impaired in glare acuity than patients with monofocal or multizonal progressive IOLs. There was no significant difference in any criteria between these two pseudophakic groups. Subjects with a clear cristalline lens had statistically significant better results compared with all other groups. CONCLUSIONS An increase in glare sensitivity and the appearance of halos are more important in patients with even minor cataracts than in any pseudophakic population. As a consequence of this study, night driving ability should be carefully examined in any pseudophakic patient, but also in any subject with even beginning cataract.