Comparison of three corneal trephines for use in therapeutic penetrating keratoplasties for large corneal perforations.

Corneas with large perforations complicate penetrating keratoplasty due to the increased risk of anterior chamber collapse they pose. We hypothesize that suction trephines should produce more uniform corneal openings than non-suction trephines. Penetrating keratoplasties using Franceschetti-type freeblades, and Hanna and Hessberg-Barron suction trephines were performed on human eye bank eyes with large corneal perforations. The trephined corneas' histologic appearance was graded according to depth, sharpness, and perpendicularity of cut. Suction trephines were easier to use, resulted in less anterior chamber collapse, caused less corneal distortion, and created a sharper, deeper and more perpendicular incision. The Hessberg-Barron and Hanna trephines performed better than the freeblades in this study.