[Penetrating keratoplasty in free form using the excimer laser--first application in a patient]

Conventional mechanical trephination techniques limit penetrating keratoplasty to the use of circular transplants. Certain special indications, however, would profit from the application of non-circular transplants. We describe our first case, in which we applied a newly developed technique for congruent trephination of donor and recipient cornea in free form with the excimer laser in a patient.

Excimer laser trephination was applied on the cornea of a 74-year old female patient who presented with a perforated peripheral corneal ulcer. The affected corneal tissue was replaced by an individually adapted transplant. Trephination was achieved by a 1.0 mm laser beam, which was guided along a predetermined pathway.

Excimer laser trephination achieved completely congruent dimensions of donor button and recipient bed in a kidney shape. Laser trephination was carried out nearly down to Descemet's membrane. The cut in the remaining deep tissue was completed with a diamond knife. The postoperative course was uneventful. Follow-up at four months postoperatively showed a well healed clear transplant, which did not reach the optical axis of the cornea.

This first application of the newly developed trephination technique represents a valuable addition in corneal transplant surgery in special indications. In the case demonstrated here, an eye with perforated corneal ulcer could be visually rehabilitated rapidly with only a minimal volume of transplanted tissue.