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

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

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.

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.

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