The Hanna suction punch block and trephine system for penetrating keratoplasty.

We describe a new system for corneal trephination. The system for cutting donor buttons consists of a concave Teflon well in which the donor corneoscleral shell is secured by gentle suction. A cylindrical guide ensures that the disposable razor blade trephine is centered and is perpendicular during punching from the endothelium. The suction mechanical trephine used for the host has the following features: (1) a gun-sight alignment system for reliable centering, (2) a 360 degrees limbal suction ring that secures the trephine to the eye and ensures perpendicularity of the cut, (3) support surfaces on either side of the disposable razor blade that support the cornea during cutting to create near-vertical uniform wound margins, (4) rotation of the trephine with a manually operated gear system for smooth cutting, and (5) a calibration device that governs the extension of the blade and also allows cutting without descent of the blade.