Effect of improved intraocular lenses on contrast sensitivity tests.

Refractive surgery is a surgical treatment, which aims for the correction of refractive errors. Nowadays, there is a strong tendency to perform refractive surgery in such a way that spherical aberration and other optical abnormalities after the operation are minimal. In patients with cataract, this can be achieved by replacing the cataracteus lens by a synthetic aspherical IOL (intra-ocular lens). An aspherical IOL contains negative spherical aberration which compensates the positive spherical aberration of the cornea.

Implantation of aspheric IOL's results in higher visual performance than spheric IOL's.

Two groups of 30 patients, each group tested with a specific intraocular lens (IOL) type in a spheric and aspheric design. In each patient a spherical IOL is placed in one eye and an aspherical IOL in the fellow eye. The IOL's used in the first combination are acrylic based and the IOL's used in the second combination are silicone based. Both combinations of IOL's are CE-approved. After implantation of the IOL in the second eye, the patient will perform two different contrast sensitivity tests at optimal refractive state of the eye and at -2D, -1D, +1D and +2D defocus. In this studie, the spherical aberration, corneal topography and stray light will also be measured.