Perioperative treatment and prognostic factors for penetrating keratoplasty in Acanthamoeba keratitis unresponsive to medical treatment.

Background: The purpose of this research is to evaluate the prognostic factors for graft survival after penetrating keratoplasty (PK) for medically unresponsive Acanthamoeba keratitis.

Methods: In this retrospective, interventional case series, 22 affected eyes underwent therapeutic penetrating keratoplasty for medically unresponsive Acanthamoeba keratitis at Shandong Eye Institute during a 10-year period (1996-2006). Diagnosis of Acanthamoeba keratitis was made prior to surgery for 15 eyes, while a delayed diagnosis was made for the other seven eyes. Appropriate anti-microbial agents were administered based on the suspected etiological agents. Intravenous hydrocortisone was given only once in two patients. Systemic and topical use of steroids was avoided within 2 to 3 weeks after operation. The six patients who were misdiagnosed had intravenous hydrocortisone for 3 days postoperatively, and routine administration of systemic and topical steroids until Acanthamoeba was detected. Patients were followed up for 6 to 24 months (mean, 10 months) after PK.

Results: Of these patients, none wore contact lenses. The possible causes for infection included trauma with plant matter or dust (13 cases), poultry-feeding (six cases), and occupational exposure to oil (one case). Eighteen grafts were clear at the end of the follow-up. Six eyes (28%) had amoebic recurrence at 2 to 3 weeks after PK, of which five were misdiagnosed prior to surgery and received postoperative corticosteroids treatment. Four of the six eyes that developed a recurrence were regrafted, while the other two remained clear for the ensuing follow-up period.

Conclusions: PK may be performed in eyes with active Acanthamoeba keratitis. To improve the prognosis, surgeons should pay attention to antiamoebic therapy and avoid prescribing corticosteroids in the early postoperative period.