Variation in corneal graft size related to trephine technique

To determine the range of variation in corneal transplant tissue size induced by slight changes in trephination technique, four human corneas that had been stored in McCarey-Kaufman medium and 11 intact human globes were used. Endothelial surface trephination yielded a smaller corneal button than epithelial trephination. In the intact eye, the higher the intraocular pressure was, the larger the resulting corneal diameter. With use of a trephine with a central plunger, the higher the obturator was, the larger the diameter of the resulting tissue. Also, the duller the trephine was, the larger the diameter of the cut, due to difficulty in tissue penetration. Thus, slight variations can markedly affect the match in size between donor and recipient.