THE TAMPA TREPHINE TECHNIQUE WITH CAT CORNEAL ENDOTHELIUM

The Tampa Trephine (Martin Marietta Speciality Components, Large, FL, U.S.A.) penetrating keratoplasty technique uses a 7.0-mm corneal donor button with six rectangular 1 x 2-mm tabs of Bowman's layer, 75 mu m in thickness, which are inserted into the recipient stroma beneath Bow man's layer. We evaluated the safety of the Tampa Trephine tissue-trep hination method on the cat corneal endothelium combining vital stainin g and scanning electron microscopy, comparing it with the standard Wee k trephination technique. The Tampa Trephine tissue trephination produ ces a donor button with a 6.7-mm diameter central area of normal endot helium. Localized peripheral areas of cellular loss, endothelial and D escemet's tears, endothelial detachment, and folding along the border of the trephination were observed with the Tampa Trephine method, all located in an area of less than or equal to 150 mu m, adjacent to the edge of the button. Standard trephination induced a localized peripher al area of endothelial damage <50 mu m in extension from the donor edg e. A theoretic maximal 8.4% peripheral endothelial cell loss is induce d with the Tampa Trephine trephination method, compared with a 2.8% lo ss with the standard procedure. The peripheral location of the alterat ions after the Tampa Trephine does not hinder the viability of the cor neal endothelium, as it has been clinically observed.