ULTRASTRUCTURE OF CLEAR CORNEAL INCISIONS - PART-I - EFFECT OF KERATOMES AND INCISION WIDTH ON CORNEAL TRAUMA AFTER LENS IMPLANTATION

purpose: To examine the ultrastructure of clear corneal incisions (CCl s) performed with diamond keratomes and steel blades as well as the co rneal trauma after implantation of a foldable intraocular lens (IOL) t hrough two incision widths. Setting: University Eye Clinic and Institu te of Histology and Embryology II, University of Vienna, Austria. Meth ods: Twenty-four human cadaver eyes without prior ocular surgery were obtained from the University Eye Bank, Vienna. Single-plane CCls were performed with 3.0 and 3.2 mm Alcon steel blades and with a 3.0 mm Huc o diamond keratome. The AMO PhacoFlex ii lens was implanted with a Fin e II folder. During the entire procedure, the eye pressure was kept be tween 26 and 30 mm Hg by infusing balanced sail solution into the ante rior chamber. Specimens were prepared for light microscopy, transmissi on electron microscopy, and scanning electron microscopy according to standard procedures. Results: The diamond keratome produced cleaner cu ts than the steel blade. After IOL implantation, 3.0 mm steel blade in cisions exhibited extensions at their lateral ends. Within these exten sions, the collagen lamellae were displaced and torn. This was not tru e with 3.2 mm tunnels. Because of the thickness of a 3.0 mm diamond ke ratome, the extent of corneal trauma was between that found with 3.0 a nd 3.2 mm steel keratome tunnels. Conclusions: implantation of the SI- 30 through 3.0 mm CCls produced by the steel blade led to more severe corneal trauma than implantation through 3.2 mm steel blade incisions or 3.0 mm diamond keratome incisions. Thus, IOL implantation through i ncisions that are too small intensifies corneal trauma.