Peripheral Endothelial Cell Damage After Trephination of Donor Tissue

PURPOSE:To evaluate and quantify the degree and pattern of donor endothelial cell damage, which occurs with mechanical trephination of donor corneal tissue. METHOD:Twenty donor corneal-scleral tissues were used for these paired experiments. The tissues were randomized for trephination with 10 tissues trephinated by an 8.0-mm-diameter Barron trephine (Katena, Denville, NJ), and 10 tissues trephinated with an 8.0-mm-diameter UltraFit Coronet trephine (distributed by Angiotech, British Columbia, Canada) by the same investigator. Trephinated corneal buttons were then stained with vital dye stain, and the endothelial layer image captured with digital photography. The images were then analyzed by digital planimetry, and the pattern and quantity of endothelial damage was determined by an investigator who was masked to the specific trephine used for the individual tissue. RESULTS:Trephination created a pattern of circular damage at the edge of the donor button in every case with no break in continuity of the circle, but some portions of the circle were wider than others. Occasional, scattered, peripheral small areas also displayed damage, but no significant striae, stretch, or other central damage was noted in any donor. The mean percent damage in the series was 6.35% ± 0.90% (range4.33%-7.78%). The UltraFit Coronet trephinations averaged damage of 5.64% ± 0.85% (range4.33%-6.69%), and the Barron trephinations averaged damage of 6.50% ± 0.95% (range4.92%-7.78%). Although 8 of 10 experimental pairs of trephinations demonstrated less peripheral endothelial damage with the UltraFit Coronet trephine, the mean damage between each group did not reach statistical significance in this small series. (P = 0.08) CONCLUSIONS:Donor mechanical trephination of full-thickness corneal tissue creates relatively consistent amounts of peripheral edge damage and likely no central endothelial damage. There may exist differences in edge damage between different mechanical trephination systems, and a direct comparison to laser-created trephination is needed.