To describe a technique to completely replace the donor corneal carrier of an existing type 1 Boston keratoprosthesis (KPro) that preserves the hardware intact.
Two eyes with sterile corneal melts around the KPro stem underwent a complete exchange of the donor corneal carrier. Donor corneas were prepared in the usual fashion for KPro and were then left uncovered to dehydrate. Meanwhile, the melted corneas were excised in a manner similar to that for failed penetrating grafts and uncollared from the KPro. The new donors were then sufficiently thinned to slide between the back and front plates; however, to clear the 5.0-mm KPro front plate flange, the central 3.0-mm opening in the replacement donor corneas was first enlarged by means of 2 paired sub-1.0-mm radial relaxing incisions placed 180 degrees apart. Once positioned, the new donor carriers were rehydrated to seal the space between the back and front plates.
The full-thickness corneal carrier was successfully replaced in both cases. In 1 case, scarring of the back plate holes caused the plate to behave like an intact Descemet membrane during deep anterior lamellar keratoplasty.
When an otherwise functional KPro is jeopardized because of disorders of the donor corneal carrier, it can be advantageous to selectively replace the carrier and thus salvage the original KPro. We describe such a rescue technique, which permits the exchange of the corneal carrier without disassembling the KPro.