Toric Intraocular Lens Misalignment Inducing Astigmatism After Refractive Surgery

PURPOSE: To report the unexpected induction of astigmatism after phacoemulsification and toric intraocular lens (IOL) implantation in an eye with previous corneal refractive surgery. METHODS: Case report of a 46-year-old man with bilateral nuclear cataract and previous photorefractive keratectomy. Because corneal topography identified regular corneal astigmatism at the central optical zone, phacoemulsification and implantation of a one-piece hydrophobic acrylic toric IOL were performed. RESULTS: Unexpected induction of astigmatism occurred in the first operated eye despite proper alignment of the IOL according to the preoperative calculations using simulated K values to determine toric IOL power and alignment. A retrospective qualitative analysis of corneal topography showed mismatching of the steepest meridian, leading to an off-axis IOL. Secondary IOL rotation improved both uncorrected and corrected distance visual acuity. CONCLUSIONS: Qualitative analysis of the corneal topography is mandatory during the assessment of toric IOL alignment in eyes with previous corneal refractive surgery to identify the actual location of the steepest meridian.