Clinical features and outcomes of Acanthamoeba keratitis in a tertiary hospital over 20- year period

Abstract

Purpose: To analyze the outcomes of Acanthamoeba keratitis (AK) in terms of different clinical presentations in a tertiary hospital in Taiwan over a 20- year period. Methods: This is a retrospective case series. Patients with AK diagnosed at the National Taiwan University Hospital between January 1996 and December 2015 were identified. A diagnosis of AK was made on the basis of positive Acanthamoeba smear/cultures or pathological identification of Acanthamoeba cysts on keratoplasty specimens. Patient demographics, clinical presentations, treatment courses, and final visual outcomes were collected and analyzed. Visual acuity, postoperative complications and graft survivals were measured as outcomes. Results: Of the 62 patients with AK in our study, 64.5% were medically treated while 35.5% underwent surgical treatment. In those with ring infiltrate, 52.4% patients could be successfully treated with medications. In eyes receiving penetrating keratoplasty, postoperative complications were more common in therapeutic penetrating keratoplasty (TPK) than those in optical penetrating keratoplasty (OPK) group (82.4% versus 40%, p = 0.04). The graft size was larger in TPK than that in OPK group (8.56 versus 7.83 mm, p = 0.002). Furthermore, post-operative glaucoma, which was the major complication, was found to be associated with larger graft size (p = 0.02) and dilated pupil/iris atrophy (p = 0.01). Conclusion: Even in advanced cases with ring infiltrate, eradication of infection with anti-amoebic drugs is possible. In those requiring keratoplasty, the surgical timing should be made meticulously considering graft size and signs of dilated pupil/iris atrophy in terms of post-operative glaucoma. Keywords: Acanthamoeba keratitis, Penetrating keratoplasty, Post-keratoplasty glaucoma