**2.2 Clear remaining corneal tissue in recipient**

A corneal surgeon must be vigilant to remove every opacified or scar tissue from the stromal bed. Involvement of the DM and adjacent tissues with scarring could be considered a contraindication for DALK surgery.

Manual Deep Anterior Lamellar Keratoplasty 57

transplantation. It should be emphasized that removing adequate stromal tissues near the trephination wound is as important, if not more important, than doing so in the central cornea. If the task is not performed, the Bowman-to-Bowman opposition of the donor and recipient will occur by excessive force over the sutures and unpredictable visual results will occur when sutures are removed or when sutures lose their tensile strength. The ideal situation is provided by the TALK procedure in which the DM is exposed in the entire trephination wound area. In TALK cases, early removal of corneal sutures can be

**2.9 Minimal irregularities of the anterior surface of the donor tissue over the optical** 

suture site, the less the amount of irregularity at the specific point.

optical zone from adverse effects of the sutures all around the wound.

Given a donor cornea devoid of any preexisting pathology, the corneal sutures will be the major source of irregularities of the anterior corneal surface. In fact, the irregularities originate from the suture sites and radiate over the corneal surface vanishing toward the central area. So the further the distance between a given point over the corneal surface and a

If we liken the irregularities that originate from the sutures to the cold winds and the optical zone to a freezing man, it could be said that cold wind of irregularities blow from the suture sites toward the optical zone so the best way to protect the freezing man in the optical zone from the cold wind of irregularities will be to put it at the center of the circle (Figure 1) Hence, selection of the pupil center as the center of the trephination wound protects the

Fig. 1. Visual axis can be kept away from the sutures at the center of the circle just as the

Freezing man keep himself away from the cold winds.

accompanied with good visual results.

**zone** 
