Complications of penetrating keratoplasty: graft infections.

Microbial infection of a corneal transplant is a complication that is a bane to all corneal surgeons, the sequelae of which can be devastating. Identified risk factors include exposed, loose, or broken sutures; persistent epithelial defects or severe punctate keratopathy; soft contact lens wear including therapeutic lenses; graft hypoesthesia; kerato-conjunctivitis sicca; previous herpetic eye disease; graft failure; ocular adnexa and lid abnormalities; and ongoing external and corneal infections. Management includes preventive measures, microbiologic diagnostic procedures, and antibiotic therapy. Infectious crystalline keratopathy is a unique corneal infection that predominantly occurs in corneal transplants. It is characterized by the slowly progressive development of needle-like opacities in the corneal stroma and is most commonly caused by streptococcal species. Another group of infections that occur in grafts is recurrence of an infectious process for which the patient was originally grafted. Two notable pathogens in this group include Acanthamoeba and herpes simplex.