LAUSR

PURPOSE Wavelength dependence of diffractive intraocular lenses (IOLs) was recognized in vitro but not yet assessed in vivo. By examining pseudophakic patients who had extended-depth-of-focus diffractive implants, we clinically measured this spectral effect on their vision. We also tested the lens in vitro. DESIGN Cross-sectional study with laboratory investigation. METHODS Twelve patients (23 eyes), all pseudophakic with a Symfony lens, were measured monocularly in red and white light at far, intermediate and near. Corrected distance visual acuity (CDVA), distance corrected intermediate and near visual acuity (DCIVA and DCNVA) were assessed. Contrast sensitivity was examined at several spatial frequencies. The in-vitro lens modulation transfer function (MTF) was measured, under different spectral conditions, using an IOL metrology device. RESULTS CDVA was comparable in red and white light. DCIVA and DCNVA were significantly better in white light by 0.06 and 0.09, respectively. Contrast sensitivity was slightly better with a red filter at far, but it was worse at intermediate, though differences were significant only at one frequency. Near contrast sensitivity was better in polychromatic than red light, which was significant at three frequencies. The in-vitro analysis confirmed Symfony's wavelength dependence: performance is improved at far, but is worse at intermediate and near. CONCLUSIONS Symfony's spectral dependence was observed to affect visual acuity and contrast sensitivity. Although the red filter did not improve distance vision, it caused visual deterioration at near. One might take this effect into account when optimizing the reading performance of patients with diffractive IOLs.