Induced corneal astigmatism using an asymmetric corneoscleral tunnel and a large-optic intraocular lens

To prospectively evaluate the induction of corneal astigmatism using an asymmetric corneoscleral tunnel incision (J-incision) to implant large-optic (7.0 mm) intraocular lenses (IOLs).

Department of Ophthalmology, University of Bonn, Germany.

Thirty-five patients had sutureless phacoemulsification with implantation of a 7.0 mm poly(methyl methacrylate) posterior chamber IOL using an inverse J-shaped asymmetric tunnel incision. The corneal astigmatism was measured by corneal keratometry and topography preoperatively and 1 day and 1 and 3 months postoperatively. Induced astigmatism was calculated by vector analysis.

Mean induced changes in the corneal radii measured by keratometry were 0.17 mm +/- 0.14 (SD) on the first postoperative day, 0.18 +/- 0.14 mm after 1 month, and 0.17 +/- 0.14 mm after 3 months. Mean postoperative induced astigmatism measured by corneal topography was 1.08 +/- 0.66 diopters (D), 0.89 +/- 0.78 D, and 0.85 +/- 0.70 D, respectively. No signs of wound instability were detected.

An asymmetric corneoscleral incision was suitable for implantation of large-optic IOLs, resulting in immediate stability of the induced cylindrical power in the central 3.0 mm zone as measured by keratometry. A reduction in induced corneal astigmatism can be achieved using this technique versus using symmetrical wound constructions and large-optic IOLs.