Therapeutic Penetrating Keratoplasty

Therapeutic keratoplasty (TPK) refers to replacing a diseased host cornea with a full-thickness donor corneal tissue to eliminate the infectious disease focus. TPK is routinely performed for non-resolving microbial keratitis such as bacterial, fungal, acanthamoeba, and viral keratitis. TPK, if performed to repair the anatomical defect as perforation or descemetocele, is called tectonic keratoplasty. TPK aims to resolve the infectious foci and restore tectonic integrity with a terminal aim of visual rehabilitation. TPK and tectonic keratoplasty make up significant proportions of corneal transplants performed worldwide, especially in Singapore and other developing nations. In TPK, the host cornea is trephined 0.5-1 mm larger than the infiltrate size, and 0.5 to 1 mm larger donor corneal tissue is prepared. The infected cornea, along with anterior chamber exudates, are removed, peripheral iridectomy is made, and lens removal is done based on the indication, followed by suturing of the donor tissue to the host rim with a 10-0 nylon suture. In the end, peripheral anterior synechia is released, the anterior chamber is formed, and intracameral moxifloxacin is given. The aim is to restore anatomical and functional ocular integrity and eliminate the infective focus. TPK can have multiple intraoperative and postoperative complications. Preoperative antimicrobial therapy reduces the microbial load, and postoperative antimicrobial therapy for 3 or 4 weeks is mandatory to prevent infective sequelae. Steroids are initiated after a brief period of quiescence when the eye is free of infection for graft survival.