Penetrating corneal graft; orientation of the initial penetration of the trephine into the host cornea.

DURING the operation of perforating graft of the cornea, the trephine in the great majority of cases enters the anterior chamber in only a portion of its circumference, the remaining circumference of the graft being completed with scissors. The author has noticed, both in operations performed personally and in those performed by others, that the portion of the circumference of the trephine which first enters the anterior chamber is usually that nearest to the wrist of the operating hand, despite the customary effort of mzaking an even trephine cut. Since this was first noted, particular attention has been directed to it, and it has been found that in all of six perforating graft operations performed during a period of 3 weeks the trephine entered the anterior chamber on the wrist side. To confirm this observation, sixteen enucleated eyes were trephined with the same care as would be used in the operating theatre for the recipient eye. That is, the trephilhe cut was stopped as soon as it was clear that the anterior chamber had been entered. In five cases the anterior chamber was entered practically simultaneously in the entire circumference of the trephine cut, and in the remaining eleven cases, the anterior chamber was entered nine times on the wrist side, and twice on the other side. The fairly large proportion of cases (six out of sixteen) in which the whole circumference of the trephine reached the anterior chamber simultaneously was probably due to the relative confidence of the laboratory as compared with the operating theatre. It would appear that, so far as the author is concerned, there is a tendency to tilt the trephine in the direction of the wrist of the hand holding it, despite the effort to keep the instrument vertical.