Computer modeling of visual impairment caused by intraocular lens misalignment

Abstract Purpose: To evaluate a computer program to modulate the visual impairment caused by intraocular lens (IOL) misalignment and visualize results obtained by numerical calculations. Setting: Department of Ophthalmology, Medical Faculty of Charles University, Prague, Czech Republic. Methods: The optic imagery of a Landolt circle was calculated using a ray-tracingcomputer program. Visual aberrations resulting from a decentered and/or tilted IOL were studied using this program and compared with theoretical calculations. Results: The IOL decentration and/or tilt shifted the postoperative refractive errorstoward myopia and astigmatism (oblique). The combination of IOL decentration and tilt produced a refractive error that depended on the relationship between the geometrical axes of the decentration and tilt. The refractive error can be enhanced or diminished depending on the relationship of these axes. Conclusions: These findings verify the results calculated by paraxial vergence equations. A ray-tracing program simulated the optic imagery for various kinds of IOL misalignment and IOL optic properties.